Reasons Behind Tulowitzki’s Power Surge

Troy Tulowitzki‘s been on a tear this season. But this isn’t some small-sample, month-long streak. He’s been raking since last July, after he returned from a wrist injury that sidelined him for nearly five weeks.

Usually when a hitter returns from these types of injuries it takes awhile to hit at pre-injury levels. It’s pretty obvious to understand why: Batters use their wrists to swing through the ball. In Tulo’s case, though, it’s almost as if he never suffered the injury.

The 26-year-old is enjoying the best run of his career, producing a slash line of 0.329/0.403/0.671 since the injury while helping lead the Rockies to a league-best 12-3 record this year. Given Tulowitzki’s injury history, how has he been able to do this?

I took a look at his directional hitting first, to get a sense of where he’s hitting his line drives, fly balls and home runs. I wanted to see if there was a trend. For this, I used MLB’s batted-ball data, which gave me the angular direction of each hit (-45 degrees is down third base; +45 being is down first base. Next, I inserted a Loess curve to to detect any data changes. Here is a look at his direction distribution over the years of all line drives, fly balls and home runs:

Pretty simple, right? Tulowitzki is turning on the ball more than he has at anytime in his career. This change has allowed him to put the ball into the left-field corner, and the corners are usually the shortest part of the field — which increases the chances of a home run.

After looking at the data, I think two factors could be working together that have allowed him to return so dramatically from his injury.

First, Tulowitzki, with the help of Jim Tracy, changed his swing in early 2009. That gave him more bat speed. With the extra speed, he turned on the ball faster and pulled it more. You can see in the above graph — in the middle of 2009 — when he began to hit the ball more often to left field.

The second factor that might be driving this power surge is that he’s stayed healthy. That’s no small accomplishment for a player who’s lost nearly 110 games to injury since 2007:

06/05/07 Missed 1 game (right groin).
07/26/07 Missed 2 games (illness)
06/20/08 Missed 46 games (quadricep injury) on DL
07/21/08 Missed 13 games (right hand injury) on DL
05/15/09 Missed 1 game (elbow injury)
06/06/09 Missed 3 games (left hand injury)
08/22/09 Missed 1 game (viral infection)
09/11/09 Missed 3 games (back injury)
05/13/10 Missed 2 games (right quadricep)
06/15/10 Missed 2 games (groin)
07/27/10 Missed 33 games (wrist injury) on DL
09/01/10 Missed 2 games (groin)

Basically, Tulowitzki has been hurt. A lot. But look at his most recent wrist injury this way: The time he was forced to sit might have helped him heal from any lingering ailments that might have taken him down. After all, playing injury free is only going to help a player be more productive. Perhaps it was a perfect storm for Tulo’s power — a change in his hitting approach, plus pain-free baseball.

Tulowitzki’s production improvement since his return has him among the list of the game’s most elite players. Is he the best? I’m not ready to put him there yet. His production has increased as he’s been able to pull the ball into the short left-field corner. Whether it’s driven by his new stance or finally getting over his past injuries, he’s helping Colorado. And that’s all that matters.

Thanks to Andrew Martin at for helping with some background information.

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Jeff writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first season in Tout Wars, he won the H2H league. Follow him on Twitter @jeffwzimmerman.

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“Reason’s”? Really?