T.J. Rivera Looks Like the Real Deal by mojohill July 19, 2017 T.J. Rivera has had a remarkably unlikely path to the majors, going from an undrafted free agent to now the Mets’ starting third baseman. He has always had his doubters, and still does, but he got to the majors by consistently putting up around a .300 average in the minors with an above-average OPS despite his lack of walks and power. In 2016, a hitter-friendly park helped him enjoy a career year in Triple-A, winning the PCL batting title with a .353 average, a .909 OPS, a 142 wRC+ and a promotion to the majors for the first time in his career at the age of 27. He continued his success into the majors, where he was a key piece in the Mets’ 2016 Wild Card run. He was able to replicate the numbers he had put up during his entire minors career, batting .333/.345/.443 with a 119 wRC+ in 113 plate appearances. Rivera’s impressive and somewhat surprising debut stint in the majors eased some of the concerns scouts had with his game, but plenty of people still had their doubts. The expectation was that Rivera would not be able to hit for a .300+ batting average in the majors like he did in the minors due to the tougher competition and better defenses. Rivera proved them wrong by hitting .333, although he was admittedly helped out by an unsustainable but certainly not outrageous .360 BABIP. Rivera posted BABIPs comfortably over .300 in the minors, so while some regression seemed to be in store for his future, it was certainly not crazy to predict that Rivera would still be able to hold a .300 average in the majors. If he had any chance of becoming a full-time starter at the highest level, he was going to need to keep that batting average in the vicinity of .300 to make up for his lack of other skills, such as patience, power, and defensive ability. Rivera has always been known as a line-drive hitter with an aggressive approach at the plate. He likes to swing early in counts, and as a result he doesn’t walk much, but at the same time he is a contact hitter and doesn’t let his aggressive approach negatively affect his strikeouts. He doesn’t have much natural power, so for him to be successful, he just has to continue focusing on trying to hit line drives to the gaps and swinging at the right pitches. In his first sample of major-league pitching, he was able to hit line drives at an above-average rate of 23.9%, compared to the MLB average rate of about 21%. It’s worth mentioning that this rate was higher than his typical LD% in the minors, showing that he was actually hitting more line drives vs. major-league pitching than minor-league pitching. He hit ground balls at a rate of 42.4%, which was also lower than he generally hit in the minors, and of course, preventing the amount of ground balls you hit leads to more success at the highest level, especially when you’re hitting them to the best infielders in the world. This GB% was slightly lower than the MLB average of about 45%, showing that some work could still be done on his GB% but that it wasn’t a serious problem. He also may have been helped about by a bit of luck on some of these ground balls, as he had a .360 BABIP that was sure to regress a little. Rather than hitting ground balls, the thing he needed to work on was hitting fly balls, which he did at a slightly below-average rate of 33.7%. For someone with not a lot of raw power, hitting more fly balls would be beneficial to making the most of whatever power he did have. Overall, Rivera’s results in the majors had been a very pleasant surprise, don’t get me wrong. The key thing he showed in his 2016 debut is that he was not over-matched by major-league pitching, continuing to do the same things that made him successful in the minors. But in 113 plate appearances, he drew a grand total of three walks, which won’t quite cut it if you want to be an everyday starter. In addition to that, he was only making hard contact (according to FanGraphs) 27.2% of the time, below the MLB average of about 31%. Being the line-drive hitter that he was, he had the ability to hit the ball harder, and the thing he needed to do was to focus on hitting more fly balls and improving his launch angle by just a tick. This doesn’t mean that he needed to become a completely different hitter, but hitting the ball a little higher in the air more rather than on the ground or in a straight line would benefit him in not only his average but his isolated power, and also help him hit for a BABIP that would be less likely to regress. Things got off to a bit of a slow start in 2017 due to lack of playing time and a short stint in Triple-A, but as injuries have befuddled the Mets, he has received more and more playing time, and at this point has basically hit himself into a starting role at third base. As of July 15th, Rivera has hit .304/.350/.464. A chunk of this production has come in his last 10 games, where he’s hit nearly .500 en route to a 10-game hitting streak. Still, that batting line is “classic T.J.” At first glance it might seem like a small drop-off from last year, but if you look a little deeper, Rivera has actually improved in quite a few areas compared to last year. First off, he has slightly decreased his soft-contact rate since last year by 2% while increasing his hard-contact rate by 4.2%. Immediately this looks like a recipe for success; hitting the ball harder more often and softer less often cannot be a bad thing. While hitting the ball harder compared to last year, he’s also hit more fly balls, improving from a slightly below-average 33.7% last year to an above-average 40.1% this year, while also decreasing his GB% by 6.9%. So he’s hitting the ball harder, he’s hitting more fly balls, and he’s hitting fewer ground balls. These were all little things that I mentioned earlier that he could tweak to become a more polished hitter, and he has improved slowly but surely in these minor aspects of his game. But at heart, Rivera is still the same hitter, just a better version of himself. He’s still a line-drive machine, with an LD% just a tiny bit higher this year compared to last year (24.3 vs.23.9). This shows that he has improved on hitting the ball harder and in the air while still playing his usual game. And, as it should, hitting the ball harder has caused his ISO to increase from .143 to .160, meaning that he’s taking better advantage of the power he has. While he is still aggressive and still likes to swing early in counts, he’s also improved his walk rate slightly, from a measly 2.7% to a still below-average 4.5%, as Rivera’s plate discipline has slightly improved this year. Here’s a graph of his amount of pitches swung at outside the zone (blue), inside the zone (red), and overall (yellow). He’s become slightly more patient and selective, swinging at more pitches in the zone and fewer pitches out of the zone. The data also shows that he’s swinging at the right pitches, as here’s a graph of his contact rate outside the zone (blue), inside the zone (red), and overall (yellow). As you can see, he’s making contact at about the same rate on pitches in the zone, while the pitches he’s going after that are outside the zone have generally been better pitches to hit, as you can see by his increased O-Contact%. Even more importantly, he’s swinging and missing less, as last year he swung and missed an above-average 12.1% of the time while this year he’s swinging and missing at a slightly below-average rate of 10.2%. Rivera will always be a contact-first type hitter, but he’s tweaked some minor flaws in his game and is actually molding into more of an all-around hitter than people may think. So why is his batting line appear slightly worse than last year, if he’s doing so many things better? Well, it’s really only his batting average that has declined, and that’s mostly due to a BABIP .024 lower than last year. In the minors, Rivera had always been able to keep a BABIP in the mid-.300s, so with a BABIP of .336 this year and the fact that he’s hitting the ball harder and in the air, there shouldn’t be any regression this year; in fact, his batting average is more likely to go slightly up than down. He’s improved his on-base skill and power to the point where they are still below-average skills, but they are respectable enough that his excellence in hitting for average and hitting line drives outweighs them. So T.J. Rivera really seems like a major-league starter this year, proving that his amazingly consistent minor-league numbers and impressive MLB debut were not flukes. His defense is admittedly mediocre, as he’s accumulated -2.0 defensive runs in his career according to FanGraphs. But there really is no doubt that he can hit. This guy now has a .322/.367/.439 batting line in 3,225 professional plate appearances, so I think it’s time to stop doubting what he can do and let him play every day, because with the improvements he’s made in his game and the way he’s been able to adjust to major-league pitching, he absolutely deserves it.