Can Alexi Casilla sustain this pace?

It has been quite a turnaround for Alexi Casilla.

The often lamented infielder had just 19% of his balls in play become hits in April – which resulted in a pathetic .167/.227/.200 triple-slash – only to break loose offensively since the beginning of May to have 37% of his balls in play turn into hits and posting a .317/.394/.439 slash in that duration. This outburst has put Casilla’s numbers on the brink of becoming better than average for an average middle infielder.

Now, statistically-inclined thinkers may ultimately question the sample size of the 95 plate appearances heading into Sunday’s game and caution everyone that Casilla’s newfound good fortune on balls in play is likely to revert back towards his career norm of 28%. What’s more is that even during this hot streak since May 1, he’s still hitting the ball on the ground over 60% of the time with even fewer recorded line drives. The laws of batted ball nature suggest that those should start finding infield leather. Plus, using his more recent track record, such as his .232/.300/.313 batting line from 2009 and 2010, no one would expect Casilla to continue this success, right? Right?

Well, I do, at least to some degree.

Certainly Casilla’s history inspires little confidence. As mentioned above, he’s a worm-burner of hitter and is also fairly weak from the right-side. At the same time, he has a very discriminating at the plate, rarely expands the zone for pitchers and exercises a high rate of contact. All he needed was to make better contact – which he is doing at this point – and there are some indications that he could keep that up.   

Last week, 1500ESPN’s Phil Mackey caught up with Casilla and the streaking infielder told him that he and hitting coach Joe Vavra had made some changes in the cage to his mechanics that he has taken on to the field with him. According to Casilla:

"I was one day in the cage, hitting against the machine, and my stance was kind of tall…I went a little bit lower, and I was hitting the ball very good. I said, 'I should bring this to the game now.' So I feel a lot better."

Digging through the video archives, I found no real confirmation that he was getting “lower” in his stance but what did standout was the fact that Casilla has resurrected a leg-kick/weight transfer that he had implemented during his 2008 season.

Because the majority of the switch-hitting Casilla’s success and his plate appearances have come from the left-side of the plate, I focused more of my attention to those at-bats. Here are shots of Casilla’s pre-May swing:

In all three cases (all against Tampa), we see Casilla stepping towards home plate, only to stop his momentum, then restart his swing when the ball is close. In general, this method is good for high-contact and bat control but in terms of being able to drive the ball, it diminishes the contributions of the lower-half of a hitter’s body. This approach is very similar to that of Denard Span’s swing. Why has this worked better for Span than it has Casilla? To speculate, Span has quicker wrists, with a shorter, more compact swing and therefore has provided better results.

These are the same mechanics that Casilla used in 2009 and 2010. Here you see Casilla in Cleveland in 2010 (a decent year for him statistically) using the same mechanics:

Compare those to the following two shots from post-May 1:

Here you see that the front leg step and the weight transfer are fluid and in unison. Casilla is able to engage his lower-half much better. Because of that, despite putting plenty of balls on the ground, we see the ball jump off his bat much better than it had at the beginning of the season. So, while grounders still become outs at high percentage of the time, putting them into play at a greater velocity is bound to turn into hitters more frequently than those  of the slow bouncer variety (someday, Hit F/X will confirm this for me).

As I said before, this approach is reminiscent of Casilla’s mechanics in 2008, the year in which many believed he had broken through the team’s solution at second base by hitting .281/.333/.374 with 9 home runs. Here you see that very swing which is almost identical to his current model:

Like the examples from post-May 1, Casilla is using his lower-half more in his mechanics, able to generate some power (as evident by his 9 home runs that season). What is also interesting is that while Casilla swing from 2009-2011 have a propensity to have better contact, his career-best contact rate came in 2008 when he had this approach.

It is easy to remain skeptical on whether this alteration will led to sustainable production out of Casilla. Even making the changes that he has, it is near impossible for him to continue to hit safely on almost 40% of balls put into play. At some point, because Casilla has been receiving a very high portion of fastballs, opponents may alter their game plan – throwing more off-speed and breaking balls - in order to disrupt Casilla’s new approach. Or perhaps managers will decide to start using their left-handed relievers at Casilla’s spot in the lineup (which is now second) in order to turn him around and neutralize him by putting him to his inferior side.

That’s what baseball is. It is a series of adaptations from both sides. Hitters with consistent, solid mechanics and a keen understanding of the strike zone ultimately wind up sustaining their success over the course of a season. Right now, that description fits for Casilla. Had Casilla’s sudden streak come without the assistance of a change in his mechanics, I’d be more inclined to think that he would regress hard and soon. However realizing that there are some tangible, physical evidence driving this improvement I’m less prone to believe that he will experience that much of a downturn in the near future.