Hard-Hit Percentage Outliers

In the middle of June, I wrote an article looking at batted-ball data. Specifically, I grouped players into tiers based on their hard-hit percentage and looked at the statistics accumulated by the players in each group, then identified the outliers. This is a look back at that article to see if we can learn anything.

To start with, the following charts show a comparison of the correlation of other metrics to the different strengths of batted balls hit. I did this in the middle of June and will compare that chart to one I created using statistics for the entire season. In June, I used a cut-off of 150 plate appearances through June 14. This was right around the 60 game mark of the season. There were 236 players. At the end of the season, I used 350 plate appearances as the cut-off, which consisted of 249 players.

Noticeable here is the strengthening of the correlation for the power statistics with hard-hit percentage as more data came in. The three stats dealing the most with power—ISO, HR/FB, and slugging percentage—all saw an increase in their correlation with hard-hit percentage. This is true down the column until you get to batting average and BABIP, which showed a weaker correlation over a full season than over the first two and a half months. While ISO, HR/FB, and SLG all correlate with hard-hit percentage at .70 or above, batting average and BABIP are down around 0.10, and LD% is at .06.

In the June article, I separated the players into groups based on their hard-hit percentage. As you would expect, the players who hit the ball hard a higher percentage of the time were more productive hitters. Here is the breakdown again, first the chart through June 14, then the full-season chart.

Remember, these aren’t necessarily the same players within tiers in both tables. Some players could have moved from one tier to another as the season went on and more players qualified overall for the full season. The way to look at this is to go down the columns to see how the average statistics for each group change as hard-hit percentage goes down. It’s easy to see that the groups of players in the higher ranges of hard-hit percentage are more productive than the groups of players in lower ranges of hard-hit percentage. The players in the upper tier, with a hard-hit percentage of 35% and above, hit more fly balls, had more of those fly balls go over the fence, had a higher batting average, slugging percentage, and isolated slugging. Roughly 85% of these hitters had a wRC+ at 100 or better. The least productive tier was the group of players with a hard-hit percentage at 24% or below. A small number of these players were able to be league average or better hitters.

The numbers from June are similar to the numbers for the full-season. As hard-hit percentage goes up, offensive production goes up and the percentage of players who are above-average hitters (by wRC+) goes up. A similar trend emerges for ISO, fly-ball percentage, HR/FB%, and slugging percentage.

The interesting players to me are the ones in the minority among their group of hitters. Through June 14, there were seven players in the top tier who had a hard-hit percentage greater than 35%, but with a sub 100 wRC+. These players consistently hit the ball hard but were still below-average hitters. Considering how often they hit the ball hard, I expected these players to improve and more closely match the rest of the group from this point forward. Theoretically, these are the guys with upside based on their hard-hit percentage. At least, this was my hypothesis. How did these players do over the rest of the season?

The seven players who hit the ball hard a high percentage of the time but who had a wRC+ below 100 through June 14 are shown below. The following chart shows the performance of these seven hitters before and after June 14.

*note—to determine the wRC+ of the group, I just did a weighted average based on each player’s plate appearances. The other numbers are precise totals for the group.

These players did improve as a group, with their composite batting line going from .237/.292/.387 to .252/.305/.455. They improved even though their BABIP dropped from .289 to .286. The big increase was in their power. They hit more fly balls and had more fly balls go for home runs. Their ISO increased from .151 to .203 and their wRC+ went from 86 to 106.

Two of these players had fewer than 60 plate appearances after June 14, so they aren’t very helpful to us. Of the remaining five players, two stayed close to the level they had established by June 14 and the other three showed strong improvement. Here is a closer look at these players:

Jorge Soler was essentially the same hitter before and after June 14, right down to an identical 96 wRC+. His BABIP dropped from a sky-high .383 to a still very good .339, but he also struck out less often and his hard-hit percentage dropped from 39.5% to 32.3%. His hard-hit percentages in both portions of the season suggest he should have hit better than he did, but his low fly-ball percentage limited his power. Over the course of the whole season, Soler had a hard-hit percentage of 35.9%. That puts him in the top tier. The players in this tier of hitters had an average fly-ball percentage of 38%. Soler’s fly-ball percentage was 29.8%, which corresponds with the players on the lowest tier of hard-hit percentage, those players below 24%. Basically, Soler hit the ball hard as often as guys like Adrian Gonzalez, Bryan Braun, and Yoenis Cespedes, but hit the ball in the air as often as Gregor Blanco and Alcides Escobar. While he hits the ball hard with regularity, he doesn’t hit enough fly balls to take advantage of his hard-hit percentage.

Like Soler, Jay Bruce’s overall production did not improve. His wRC+ dropped slightly, from 96 to 90 even though he maintained a high hard-hit percentage. The shape of his production changed, though. He hit for much more power, with an ISO that was .040 higher after June 14 than before, but a corresponding drop in walk rate torpedoed his on-base percentage. The overall effect was going from hitting .212/.324/.394 through June 14 to .234/.277/.457 after June 14. Jay Bruce is a mystery. He had a top-tier hard-hit percentage and hit the ball in the air frequently enough, but his production didn’t compare to the other players with similar profiles.

Mark Trumbo was one of three players in this group who did improve a significant amount. Trumbo hit .242/.276/.445 through June 14 and .276/.333/.451 after. His wRC+ increased from 93 to 119 even though his hard-hit percentage dropped from 35.2% to 31.7%. The biggest change for Trumbo was an increase in BABIP from .280 to .337 and an increase in walk rate from 4.5% to 8.0%.

Both Will Middlebrooks and Matt Adams did not have enough plate appearances after June 14 to tell us much of anything.

Steve Pearce improved his wRC+ from 79 through June 14 to 106 from June 15 on even though his hard-hit percentage cratered from 35.6% to 25.4%. His BABIP was nearly the same. His walk rate and strikeout rate changed very little. He didn’t improve his on-base percentage by much. The big difference was an increase in slugging percentage from .365 to .471 with a corresponding increase in ISO from .153 to .248. He did this by greatly increasing the number of balls he hit in the air. His fly-ball rate through June 14 was 39%. After, it was 53%. That seems like a drastic change to me, so I wonder if Pearce made the decision to go all out for power by hitting fly balls as often as he could.

The final guy on this list was the greatest success story of this group, Matt Kemp. Kemp was terrible in the first part of the season. When I initially wrote about batted-ball data on June 14, Kemp was hitting .249/.289/.340 even though his hard-hit percentage of 35.8% was in the upper tier of hitters. From June 15 on, Kemp hit .270/.328/.519 with a hard-hit percentage of 45.5%. He hit fly balls at a higher rate (31% to 39%) and more of those fly balls left the yard (3.4% HR/FB% to 20.6% HR/FB%). Kemp’s ISO improved from .091 to .242 and his wRC+ went from 78 to 133.

This is a small group of players, so it is not an in-depth study. Also, two of this group of seven players didn’t have enough plate appearances to be meaningful. Of the remaining five players, three did significantly improve, while the other two continued their subpar ways.

The other group of hitters that interested me was the group of nine that had a wRC+ greater than 100 despite a hard-hit percentage below 24% through June 14. These players were somehow able to be above-average hitters despite carrying such a low hard-hit percentage.

The following chart shows these nine players (out of a group of 44) who had hard-hit percentages below 24% but with a greater than 100 wRC+. The top chart shows what they did through June 14 and the bottom chart shows what they did from June 15 on. My hypothesis was that these players would hit worse because their low hard-hit percentage would not let them sustain their above 100 wRC+.

As a group, these nine hitters went from hitting .313/.366/.404 through June 14 to .271/.315/.386 after June 14. They saw their combined wRC+ drop from 117 to 91. Only three of these nine hitters continued to have a wRC+ over 100 from June 15 on. The glaring change in BABIP from .353 to .303 for the group is likely a main culprit in their diminished production. They also walked less often and struck out more often.

Nori Aoki was the leader in wRC+ among this group of hitters on June 14^th. Had he been able to sustain that for a full season, it would have been a career year. Unfortunately, he suffered a broken leg when he was hit by a pitch from Carlos Frias about a week later and wasn’t the same hitter when he came back. He also dealt with concussion issues and didn’t play after September 3. He was much worse after June 14 but injuries were obviously a big factor.

Jacoby Ellsbury was already on the DL with a knee injury at the time I wrote the original article. He missed close to seven weeks in May, June, and July and really struggled upon his return. His hard-hit percentage was just slightly lower than it had been before but his BABIP plummeted from .379 to .261 and his walk rate dropped significantly also (11.2% to 4.8%). Like Aoki, injuries were probably a big factor in Ellsbury’s diminished production.

Jose Iglesias also dealt with an injury, like Aoki and Ellsbury, but his was in September and cause him to miss the last month of the season. He had already declined from a 125 wRC+ through June 14 to an 80 wRC+ from that point forward. His BABIP dropped from .367 to .302 despite an increase in hard-hit percentage from 13.7% to 17.9%. Even with that increase, a 17.9% hard hit percentage is ridiculously low. With a hard-hit percentage that low, I wouldn’t expect Iglesias to be anywhere close to a league-average hitter going forward.

Billy Burns had the lowest hard-hit percentage (13.6%) of any qualified hitter over the entire season and the highest soft-hit percentage (30.5%). He rode a .366 BABIP to a well above average 120 wRC+ through June 14. From that point forward, his wRC+ was 97, with a BABIP of .328. Over the whole season, Burns had a 102 wRC+ despite such a low hard-hit percentage. Like Iglesias, I wouldn’t expect Burns to be league average as a hitter next year either.

Salvador Perez and Jace Peterson both increased their hard-hit percentage but still saw a drop in their wRC+ by a significant amount. Perez had fewer fly balls leave the yard (15.2% HR/FB% to 10.6% HR/FB%) and his already mediocre .292 BABIP dropped to a less-than mediocre .257. Peterson had a 106 wRC+ and .339 BABIP on June 14, with a hard-hit percentage of 23.8%. From that point forward, his hard-hit percentage was an improved 27.6%, but his BABIP was .266 and he had a 63 wRC+.

Yunel Escobar and Ian Kinsler were the only two players among this group of nine who saw an increase in wRC+ after June 14. They also greatly increased their hard-hit percentage. Yunel’s hard-hit percentage went from 23.9% to 30.4%. Kinsler’s increased from 22.1% to 28.6%. Both of these hitters were below their career rate of hard-hit balls as of June 14 and hit closer to their career marks from that point forward, which was likely a factor in their improved production.

Dee Gordon joined Escobar and Kinsler in maintaining a wRC+ over 100, but he did see a drop from 118 to 109. His BABIP through June 14 was a ridiculous .418. From that point forward, it was a silly .357. His hard-hit percentage barely changed at all (17.7% to 17.5%). Gordon has had a very low hard-hit percentage every year of his career. His production is very dependent on a high BABIP. In the three seasons when he’s had a BABIP of .345 or higher, his wRC+ was 94, 101, and 113. In the two seasons when he had a BABIP below .300, his wRC+ was 58 and 73.

Overall, just two of these hitters had an improved wRC+ after June 14 and both of those hitters also increased their hard-hit percentage. A third hitter, Dee Gordon, had a worse wRC+ after June 14 but was still an above-average hitter (109 wRC+). The other six hitters in this group were significantly worse after June 14.

This is a look at individual outliers and there are factors beyond hard-hit percentage that come into play, but I do think hard-hit percentage can help us when analyzing a player’s production during the season.