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Wheeling and Finally Dealing: Zack Wheeler is Back and Better Than Ever

Zack Wheeler has been waiting years for an article to be written with this headline. Despite Tommy John Surgery’s increasing success rate, Wheeler is evidence of the still lingering uncertainty revolving around the procedure. Once one of the bright up-and-coming flamethrowers in the game, Wheeler was demoralized by the devastating diagnosis that he had a torn ulnar collateral ligament in March 2015, mandating repair by surgery. The typical recovery timeline issued to pitchers who receive Tommy John is a 12-16 month period, all encompassing the grueling process of post-surgery rest, physical therapy strengthening, and an interval throwing program that spans many months, finally followed by a return-to-mound program.  Wheeler attempted to make his comeback to professional baseball in August 2016, slightly more than 16-months post-surgery, but he was shut down after just 17 pitches in his first rehab start. It wasn’t until April 7, 2017, more than two years after his surgery, that Wheeler returned to an MLB mound.

Wheeler’s 2017 season could be considered a success from a health perspective, as he was able to hurl 86.1 IP in his 17 starts, but it was clear the right-hander was still figuring things out from a performance perspective. The final line on the former top prospect’s season was an ugly 5.13 ERA/5.03 FIP, amounting to a dreadful 19.5 % HR/FB rate, while his 4.17 BB/9 made it evident that his control was lacking. Wheeler’s average velocity had plummeted from its pre-surgery readings, from the 96.2 MPH he had averaged with his heater before surgery, to 95.4 MPH last season. It may seem like a 0.8 MPH drop-off should lead to a negligible difference in on-field performance, but the missing extra life on all of Wheeler’s pitches resulted in a season to forget. Wheeler’s peripherals were in agreement with the high ERA he boasted, so this was surely discouraging to everyone in the Mets organization.

Wheeler’s 2018 has been a completely different narrative. While he seemed to be getting acclimated in the first few months of the season, Wheeler has turned it up to full throttle since late May, as his average fastball velocity has accelerated to 96.3 MPH in his 9 GS in that span, from the 94.5 MPH it averaged in his first 7 GS. In Wheeler’s first 7 starts this season, his fastball’s average velocity was capped out at 95.2 MPH. Wheeler’s revival as one of the hardest throwing starting pitchers in the game began when he took the bump against Miami on May 22. Turning his fastball up to average 96.1 MPH, Wheeler punched out 9 Marlins. Five days later against Milwaukee, he sustained the extra juice on his fastball, averaging 95.9 MPH. However, the season and future still looked menacing for Zack Wheeler. His 5.40 ERA insinuated he was doomed for another dreadful season. Largely the result of an unsettling .331 BABIP induced and a diminutive 66% strand rate, Wheeler carried a far more promising 4.03 FIP/3.88 xFIP. Regardless, Zack Wheeler has been a different pitcher since the calendar flipped over to June.

On June 1, Wheeler’s fastball was zipping out of his hand even faster, clocking in at an average of 96.7 MPH, quicker than any outing since his big-league debut in 2013. The heat has been status quo for the lanky righty ever since; all signs point to Wheeler’s return to his pre-injury form that once inspired a momentous Mets-fanbase-sized wave of hype.

The plot directly below exhibits the velocity of Zack Wheeler’s fastball by month this season, and confirms that as Wheeler received his sudden boost in velocity, his ERA and FIP have both plummeted. While Wheeler’s 2018 season started on a shaky note, he has righted the ship in recent starts, to the point that he should now be an attractive asset to teams at the trade deadline.

While Wheeler has seen the largest velocity gains on his fastball since the season began, his split-finger, slider, and curveball have all marginally gained steam too. While latter changes are less noticeable to the naked eye, due to the physical nature of these offerings being slower, they are still meaningful. However, just saying that a pitcher gained velocity in isolation is meaningless. MLB hitters would prefer a pitcher throw harder if it signifies they are sacrificing some control, movement, or both.


In addition to being the beneficiary of a sudden velocity boost, Wheeler appears to have successfully reformed his approach to attacking hitters. The transition began in May, when Wheeler revived his previously abandoned sinker and started to decrease his fastball usage drastically. In April, Wheeler threw 203 fastballs, and hitters clocked this offering for a .439 xwOBA, with just a 20.6 % whiff rate (Per Baseball Savant). Wheeler’s fastball was the most prevalent pitch in his arsenal, at 56.5 %, which was a welcomed sight to batters. It was more of the same for Wheeler, as he threw 57.1 % fastballs in May. Throwing harder than ever before, Wheeler has dropped off his fastball usage in subsequent months, at a 41.3 % clip in June, and an even less frequent 37.3% rate through 2 July starts. Wheeler’s 3.44 ERA since June 1 shouldn’t blow anyone away, but it’s a vast improvement from his performance in the first 9 starts he made. His 3.39 FIP in this span indicates that the performance is legitimate.

As far as pitching goes, one of the skills that exhibits the greatest correlation from year-to-year is the ability to generate swings and misses. Wheeler has induced a Swinging Strike rate 0f 11.8% over 8 GS since June 1, higher than the 10.3% he averaged over the first 9 stars. As Al Melchior deliberated in his recent piece titled “Can We Count on Strikeouts From Mike Foltynewicz?,” there is a strong correlation between swinging strike rates and strikeout rates, with the former accounting for 69 % of the variance of the latter.   Despite this heavily-correlated relationship, Wheeler’s punch out numbers are yet to follow, as evidenced by his decline from the 23.6 % rate in the first 9 starts to 22.7 % since June 1. The correlation equation from the graph below suggests that Wheeler’s swinging strike rates since June 1 should entail a strikeout rate about 1.78 percentage points higher. With the increase in velocity accompanied, it shouldn’t be a shock that the fastball has been one of the main root causes of this increase in swinging strike rate. While averaging just 24.1 % between April and May, Wheeler’s fastball whiff rate has skyrocketed to 26.6 % in June, then again to 28.4 % in July.

As we near crunch time in the trade acquisition season, Zack Wheeler is an underrated asset who is hitting his stride at the perfect time. The month of June produced a mere .296 xwOBA for Wheeler, the lowest it’s been in any month since his return. With the disastrous 2017 season and a Tommy John surgery in his past, Wheeler is a cheaper alternative to other likely deadline trade candidates, such as Michael Fulmer, J.A. Happ, and Cole Hamels, and comes with 1 1/2 years of control. With the sudden return of his heat, Zack Wheeler is pitching as well as ever, and should provide great value to any team that acquires his services at the trade deadline.

(All Data from FanGraphs and BaseballSavant)

What’s Wrong with Gary Sanchez?

To the shock of many around baseball, “The Kraken” has been tamed so far in 2018. Before hitting the shelf with a groin injury in late June, Gary Sanchez had been in the midst of an extended scuffle at the plate. While often at the forefront of critique for his lackluster defensive showing down the stretch in 2017, Sanchez’s offensive struggles have dumbfounded many in the baseball industry. After a historically dominant multiple-month power surge in his 2016 rookie season, Sanchez backed it up with an outstanding 2017 season, to the tune of a .278/.345/.531 line, and he clobbered 33 HR, despite only playing in 122 games due to injury. Sanchez also carried an elite .253 ISO and 130 wRC+ last season, which makes his struggles in this campaign all the more shocking. 2018 has been a disaster of a season so far for Sánchez; he’s slashing .190/.291/.433, accompanied by a decline in his HR/FB% from his stellar career average of 26.1% to 18.4%. Boasting a disappointing 97 wRC+ and .313 WOBA before the injury, Gary Sanchez has largely spent his season searching for answers.

When addressing a player’s stat-line it’s imperative to look at the big picture: Sánchez’s K% is slightly higher in 2018 (23.8%) than 2017 (22.9%), as one might expect from a large decrease in batting average, but this 3.93 % increase in K% doesn’t explain anything as astronomical as an 88-point Batting Average drop-off. Sanchez’s BABIP (Batting Average on Balls in Play) is unsustainably low, currently sitting at .194, despite has career average of .278. While BABIP is dependent on many variables, such as Exit Velocity, Launch Angle Composition, Hang Time, Type of Hit, Defensive Shifts, etc, much of the short-run variance of the metric can be attributed to chance. While Sanchez’s outputs for many of main variables have veered off par from the past in 2018, none of these changes should account for anything close to a 30.2% lower BABIP than what his career average is. Further evidencing the misfortune that has slandered Sanchez’s numbers is that the backstop is carrying an xwOBA of .368, still well above the MLB average of .317 in this category. Some of the Gary Sanchez extended slump can definitely be attributed to horrific luck. His Average Exit Velocity has undergone an insignificant 0.55% decrease— nothing to be too concerned with. However, I was alarmed by seeing that his Average Launch Angle is up from 13.2 degrees in ‘17 to 15.3 degrees this season, given his previously historic HR/FB rates, so I delved its composition.

The problem isn’t so much that Gary has seen his average Launch Angle rise, it’s that his launch angle has been all over the place in 2018: it deviates in all different directions from what it’s been the past two seasons. His ideal xwOBA seems to be somewhere in the range between 20 degrees and 35 degrees, but Gary has been hitting at launch angles that have produced poor xwOBAs (both lower and higher than his ideal launch angle range). Gary’s 2017 Launch Angle %/xwOBA reveals that he was hovering around this range with a large percentage of his swings (the 8 most frequent ranges of 5 Degrees for Sanchez’s swings also happened to be his 8 best xwOBAs and they connect to form the territory of the launch angles from 0 degrees through 40 degrees. Gary’s been below Launch Angles of 0 Degrees and above 40 degrees much more frequently this year, with his 45 degree mark (Sanchez hasn’t homered in his career on any swing with a Launch Angle in this range) being his most frequent range (8.1%), up from the 3.2% last season and 5.7% the previous year. The portion of Gary’s struggles in his control shouldn’t be attributed to his higher average Launch Angle, they should be directed to his increase in frequency of connecting outside his optimal range, which is the real difference between his stellar offensive track record and current output.

I was curious how Sanchez’s HR/FB% could be so much lower this season than from the rest of his career, so this Launch Angle dilemma immediately caught my attention. Accompanied by his altered Launch Angle composition has been an increase in FB% (from 36.6% in ‘17 to 45.0% this season) and a decrease in LD% (from 21.1% in ‘17 to 14.2%). Gary’s IFFB% is also way up from 10.8% last season to 21.1% so far in this campaign. Whether it was a conscious decision or not, there isn’t explanation for why this has happened to one of the games premier HR hitters, but it’s resulted in a significant drop off in Sanchez’s HR/FB%, and limited his production across the board.

Another factor in Sanchez’s extended ’18 slump may be his aggressiveness at the plate. While his BB% has jumped from 7.6% to 11.7% since last season, he hasn’t brought the same aggressive mindset into his at-bats, in general. Sanchez has been more tentative with ambushing pitches in 2018, as his 1st Pitch Swing Rate is down from 29.2% to 24.9%, and his overall swing rate (both O-Zone Swing% and Zone Swing% have been lower than last season) is down from 47.9% to 43.8%. For a player of his abilities, Gary Sanchez has some ugly offensive numbers to begin 2018, due to a combination of poor luck, an ill-fated change in his Launch Angle composition, and increased selectivity at the plate.

The Bahr Is Set High for Newly Acquired Rangers Prospect

On a quiet Sunday afternoon earlier in July, the non-contending Texas Rangers made a splash into the trading market, acquiring veteran outfielder Austin Jackson, reliever Cory Gearrin, and prospect Jason Bahr from the Giants, in exchange for cash considerations, or a player to be named later. At first glance, the acquisitions raise eyebrows, as the AL West cellar-dwelling Rangers added big-league talent to a roster that is highly expected to undergo a complete reconstruction at this year’s trade deadline, just over three weeks away.

The move was thought to add Jackson to an up-and-coming squad of outfielders, in a transaction that wouldn’t be conducive to regular playing time for the 31-year-old journeyman. Gearrin was an added bonus in the trade, representing an experienced quality middle-relief option for Jeff Banister, with 1 1/2 years of club control remaining. However, Rangers GM Jon Daniels immediately clarified any controversy over his intent behind the move, stating  “Our primary motivation in the deal was acquiring Jason Bahr. He’s a guy we look at (as) a little bit (of an) undervalued prospect.”

Daniels further emphasized the insignificance of the acquisition of Jackson to the Rangers’ future plans, saying “we’re looking at talking to other clubs about the possibility of a trade. We’re not yet certain when he will report, or if there is potential for a second move.” To even the most intense baseball fans and avid prospect enthusiasts, the name Jason Bahr might not ring a bell, but it’s clear that Daniels envisions a bright enough future for the right-hander that he was willing to take on the spare parts from the Giants. The move appears to be a salary dump for San Francisco, as well as a route to clear playing time for prospects Ray Black and Steven Duggar, who were both called up directly following the announcement of this transaction. The focus of the trade is clearly the 23-year-old Bahr.

Jason Bahr had a roller-coaster ride of a collegiate career at Central Florida, starting out as a Redshirt Freshman, before being given a dearth of innings in his second campaign, and ultimately being cut from the roster in the following season. Bahr was given a new lifeline when UCF underwent coaching staff changes, and he ran with the new opportunity to contribute, notching 98 strikeouts in 60.3 innings, while appearing mostly as a reliever for the Knights. In just one season, Jason Bahr’s professional baseball dreams had gone from a long-shot to reality, as he was selected in the 5th round of the 2017 draft by San Francisco. A lanky 6’5″ right-hander, the Rangers are gambling that Bahr will add some strength to his 190-pound frame as a late-bloomer, but it’d be abnormal for a pitcher to still be growing into his frame in his age-23 season. This move could pay off to be a savvy acquisition by Jon Daniels, as he is essentially buying an undervalued prospect while he is on the rise. A similar deal transpired back in June 2015, when the Diamondbacks shed the $9.5 million salary of Bronson Arroyo to Atlanta by packaging it with young pitching prospect Touki Toussaint, a 19-year-old fireballer who lacked control at the time, in exchange for utility infielder Phil Gosselin. Three years later, Toussaint has developed into one of the games’ top pitching prospects, and is now on the brink of his MLB debut, as the move seems poised to pay off for Atlanta.

Jason Bahr is a project for a Rangers organization that can afford to take a flier on such a raw pitcher. While he generally sits in the low-90s with his heater, Bahr has exhibited the propensity to fire into the mid-to-upper 90s with the pitch as a reliever. In 13 starts for Single-A Augusta, Bahr accumulated a 2.75 ERA/2.93 FIP, backed up by an exemplary 11.53 K/9, ranking him 1st among all qualified SP in Single-A, in addition to a quality 2.75 BB/9, before earning a promotion to San Jose (A+). Bahr continued his dominance with San Jose, earning a 1.69 ERA through three starts, but these numbers are likely skewed by a LOB % of 100 % and an unsustainably low induced BABIP of .209. The chart below chronicles Bahr’s combination of missing bats and avoiding free passes. Out of all 516 MiLB pitchers to throw 60+ IP in 2018, Bahr ranks tied for 15th in K-BB%, a likely reason Daniels was so enticed by his skillset. The white dot shows Bahr’s promising ranking among his peers, in terms of K-BB% and FIP.

With an athletic delivery, Bahr has a high ceiling that is heavily contingent on the improvement of his still-developing secondary offerings. The development of his changeup has lagged behind the curveball’s progress so far, but if Bahr is able to establish one that is even average, giving him three serviceable offerings, he should be able to stick in the back-end of a big-league rotation. Depending on how much Bahr fills out and develops over the next year or two, the Rangers could have anywhere from a middle-leverage reliever to a late-blooming middle-of-the-rotation arm on their hands.