We all know what happened when J.D. Martinez returned from the disabled list this summer. If you forgot, or just want to relive the moment, check it out. It was pretty awesome. After that, Martinez went on quite the tear. From August 3 to the end of the season, he hit 10 home runs and hit a robust .339/.392/.553. He also had a batting average on balls in play (BABIP) of .418.
So, the question is, why? Why were his last two months so incredible, and after coming back from a severe injury no less? Come along with me as I try to crack the case.
Could it be because he did so well in the month of June, before fracturing his elbow on the 16th of the month? Prior to the injury, J.D. was batting .286 in the season to that point, but that’s largely the result of a horrid month of May in which he batted .229 and had only 15 extra base hits in over 100 at-bats. In June, however, J.D. batted .404 with 10 extra base hits in 57 at-bats, and had a BABIP of .512 (MLB average is .300).
Could it be because he is excellent in clutch situations, and fed off of the momentum of that fateful home run? Since May 19, 2014, which is the date of the first home run Martinez hit as a Tiger, he has had a BABIP of .333 in high leverage situations, compared to the MLB average of .299 in that time in the same situations. This is a possibility, but not a very likely one. The momentum of one hit continuing to fuel him for the rest of the month? That’s not very likely. FanGraphs’ “Clutch” measurement agrees, as Martinez has been below average in each of his three seasons in Detroit.
Why did he hit that home run on the 3rd of August? If you recall, it wasn’t your average high leverage, clutch situation. As Martinez stepped into the batters box and his name was announced, the crowd went absolutely crazy. The fans were already fired up from Jose Iglesias’ play to end the top of the inning, and J.D. coming in to pinch hit only fed their excitement.
After the game, Martinez said, “I wasn’t expecting to get that kind of ovation that they gave me when I was walking in,” he said “That was awesome. I couldn’t ask for anything more. If I could thank the fans individually, I would thank them. That was just really cool.”
“I was just like ‘You know what, forget this — see ball, hit ball.’ Look for the ball, and just be ready to hit,” he said. “I saw it nice and slow and just said, ‘This is it.’ I knew — I don’t know.”
The quotes provide evidence as to why he hit that home run that night. The crowd emotion and excitement transferred to him, and distracted him from his original game plan. As a result, he decided to simplify his approach and hit whatever pitch he saw.
From that we can ask how he changed his approach in the following days and weeks. Did he start swinging at more fastballs? Did he swing earlier in the count, or at more first pitch fastballs?
According to Brooks Baseball , Martinez swung at 57 percent of all four-seam fastballs he saw after August 3, compared to 49 percent before his injury on June 16. He also swung at 30 percent of first-pitch fastballs before the injury, compared to 43 percent after. Interestingly, seven of the 22 home runs J.D. hit in 2016 were on the first pitch — four in the first half and three in the second half — and four of those were fastballs. This extra aggressiveness is likely a result of a different approach stemming from the home run.
One item of note is that J.D. saw more inside pitches in the first half than he saw in the second half. Here are the heatmaps from FanGraphs (all graphs are from the catcher’s perspective).
These graphs from Brooks Baseball show Martinez’s batting average heatmaps in the first half compared to the second half.
From these we see that he hit more low pitches in the second half, which correlates to the second FanGraphs graph showing that he saw fewer low pitches in the second half. Obviously, when he hit the low pitches they stopped giving him low pitches to hit. But does this have anything to do with the post-injury hot streak? As always, there’s no way to be certain, but it could be the case.