Red Sox slugger J.D. Martinez’ batting average unsustainable

Boston Red Sox outfielder/DH J.D. Martinez has been shattering his career-high in batting average so far. How much should we expect him to regress?

Batting average can be a tricky statistic to predict. It can fluctuate wildly both in the short and long-term, sometimes for reasons outside the hitter’s control. The many factors that determine batting average have so far fallen in favor of Boston Red Sox slugger J.D. Martinez.

Martinez enters the day third in the American League with a .343 batting average. Any grumblings about a slow start after he went without a hit in his first two games in a Red Sox uniform were quickly put to rest. Martinez has been red-hot ever since, including at least one hit in seven of his last eight games.

Eventually, Martinez will fall into a slump that will shave some points off that batting average. It happens to every hitter. He’s not going to flirt with a .350 average all season. While we know that the small sample sizes of the early season typically aren’t sustainable it doesn’t mean the player can’t remain among the elite in that category all year. Martinez can still contend for a batting title even with some regression. The question is how realistic is that to happen?

His .287 career average may be a bit misleading given that the number is dragged down by a few futile years prior to his breakout in 2014. He became a completely different hitter with the Detroit Tigers after altering his swing to become a disciple of the launch angle movement.

Martinez hit an even .300 from 2014-2017. Those 1,929 at-bats over that span are a large enough sample to consider Martinez legitimately capable of reaching .300 this season. He’ll need to take it a step further to put himself in the batting title race. His previous career-high is a .315 average. Every AL batting title winner has finished with a higher average than that since Carl Yastrzemski won the award with a .301 average in 1968.

It’s feasible that Martinez could set a new career-high this season yet his average is bound to regress to some extent. His current average is inflated by a league-leading .437 BABIP that towers over the league average. That suggests he’s been a bit lucky but that’s not the whole story.

Martinez has always had a batting average on balls in play on the high side, owning a .344 BABIP for his career. That’s not all luck. The balls he puts in play fall in for hits at an elite rate in part because of how hard he hits them.

According to Statcast data provided by baseballsavant.com, Martinez is seventh in the majors with a 58.4 Hard Hit Percentage this season. He’s tied for third with an average exit velocity of 95.6 mph. He’s third with 17 barrels, which essentially measures when a hitter squares up a ball at the ideal exit velocity and launch angle.

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The ball is going to fall in for a hit when it’s mashed that hard unless it’s hit right at someone or a defender makes a great play. The high BABIP isn’t entirely a fluke. Even if it comes down a bit, his average won’t plummet because of it.

The bigger concern with Martinez sustaining a lofty average is when he doesn’t make contact. His 27.5 K% is 14th highest in the league and his 15.1 Swinging Strike Percentage is tied for seventh highest. Those marks are at or near his career-highs but not by much. We can’t expect him to cut back on the strikeouts by a significant margin. Hitters don’t normally produce a high average when they strike out this much.

Granted, Martinez is not a normal hitter. His swing may be prone to strikeouts but it’s tailored to hit the ball with maximum authority. The Statcast data confirms he’s doing that. He’s also among the league’s best with a .250 ISO and .593 slugging percentage.

His six home runs put him well off last year’s pace when he blasted 45. However, the data we have on how hard he’s hitting the ball suggests his totals will rise. When he starts hitting more homers that will partially offset the expected dip in BABIP.

There’s a canyon-sized gap between Martinez’ .343 average and the league-leading .365 average owned by his teammate, Mookie Betts. Both Red Sox stars will almost certainly see their average fall, with Martinez the more likely to see a steep decline.

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He probably won’t contend for a batting title but that doesn’t mean he won’t remain among the game’s top hitters. He’ll still hit around .300 with plenty of homers and RBI. That puts him in the running for a Silver Slugger. It may even be enough for Martinez to find his way in the MVP conversation.