In the start of the 4th inning against the Tampa Bay Rays on Wednesday night, Chris Tillman gave up a long double off the right field wall to Evan Longoria. It was the third ball hit with “home run distance” to that point in the game, the other two in fact leaving the yard. The funny thing is, the vast majority of the home runs Chris Tillman allows are solo-shots. In fact, more than 68% of Tillman’s allowed home runs (30/44) occurred with nobody on base. For comparison sake, Jake Arrieta has allowed roughly 55% of his home runs with nobody on.
This is not enough to conclude anything meaningful though. In order to do that we must take a deeper look into the numbers and what they might be telling us.
Let’s start with Chris Tillman. There are two obligatory videos for this discussion, one from the windup and one from the stretch:
Despite the windup video being a home run to Shelley Duncan, both were good pitches. The differences between his windup and stretch are fairly small, but the shortened mechanics of the stretch are worth noting. So what do the stats say?
In 2012, opposing hitters had a wOBA of .293 against Tillman with nobody on base. After at least one base was occupied though, that wOBA dropped to .252, a .041 point decrease. From the stretch Tillman struck out more batters, walked fewer, and posted a FIP nearly a full run lower than he did with nobody on. It’s possible that Tillman is more comfortable pitching from the stretch, or that with runners on he feels the need to attack hitters.
I think that Tillman could benefit from pitching from the stretch full time. Another pitcher, Yu Darvish, pitches from the stretch all the time has a more balanced split as a result. In 2012 Darvish gave up .283 wOBA with the bases empty, and a .310 wOBA with runners on. The latter figure was buoyed by a .052 point higher BABIP, so it’s really a bit closer than that. You can see Darvish’s simple mechanics in this highlight reel from his nearly perfect game.
Jake Arrieta couldn’t be more different than Tillman. With nobody on base, Arrieta gave up a .306 wOBA last season, which lead to his 3.66 FIP with the bases empty. Once a runner reached however, those figures ballooned to .362 and 4.56 respectively. Orioles fans will likely tell you that the problem was even worse than those numbers indicate. FIP does seem to like Arrieta more than reality, as he under-performed his FIP by more than 2 runs last season.
The solution for Arrieta isn’t as simple since you can’t really throw from the windup with runners on base. The question is whether or not there is something physical that Arrieta can adjust to help him with runners on base. I won’t go down the mental approach road, as we simply don’t know enough to even begin. What I will say is that if there are some small mechanical changes Arrieta can make that would help him with runners on base, that might alleviate some of the mental issues he might be having.
These splits are interesting to me because, much like L/R splits, there is a physical difference for many pitchers. While the full windup is obviously helpful to many pitchers, there might be some cases where the consistency from always pitching the same way would be more valuable. This certainly seems true for Darvish, and might apply to Chris Tillman as well.
Jeff was the owner of the Orioles blog Warehouse Worthy, which focused on making advanced statistics a part of the conversation for the average fan. Outside of baseball, Jeff is a graduate of Loyola University where he received his Bachelor’s and Master’s in Business Administration. The Maryland native currently works for an Advertising Agency in downtown Baltimore. Previously a contributor to Beyond the Boxscore, he joined Baseball Prospectus in September 2014. You can reach him at jeff.long@baltimoresportsandlife.com.