Change in delivery could be why Justin Verlander is struggling in 2013

We have danced around the subject quite a bit here this season, so I'll cut straight to the chase: Justin Verlander has not been at his best so far in 2013. Yes, his statistics are still excellent, but yesterday's start was one of several he has had this season where he has struggled to locate his fastball consistently. It hasn't affected his bottom line too much -- his peripheral statistics still measure up with the best pitchers in the American League -- but his walk rate is at its highest since 2008.

I went back through some old footage of Verlander from 2011 and 2012 to see if I could pick out something in his delivery that would signal why he is having trouble in 2013 compared to previous seasons. Surprisingly, it jumped out at me: Verlander isn't following through like he has in years past.

Take, for instance, this pitch from Game 3 of the 2011 ALDS. To provide a little context, I took this from an at-bat in the fifth inning of that game. For those that don't remember, this is the inning where Verlander struck out Jorge Posada, Russell Martin, and Brett Gardner in just 10 pitches. It is arguably the most dominant inning of his career, so it made sense to start at the top and work down.

As you can see, Verlander falls off to the first base side of the mound after the pitch, but Alex Avila's glove barely moves on the outside half of the plate.

Compare that with a pitch from yesterday's game.

The difference is slight, but Verlander doesn't fall off to the left as much as he did in 2011. Going back through this game as well as a few of his other starts in 2013 -- including his worst and best starts in Houston and Arlington, respectively -- I noticed that this was a consistent trend.

Here's a pitch from the stretch from 2012, and you'll see that he falls off to first base, just like in 2011.

Again, the differences here are slight, and Alejandro De Aza squaring to bunt in the above image probably doesn't help.

That said, this could be the mechanical issue that is throwing off Verlander in 2013. It makes sense that he would want to adjust to a more balanced follow through. It leaves him in a better defensive position which, among other things, gives him more time to react at a line drive screaming back at his head. It may also be an attempt at improving his career longevity, or ease his adjustment into a new pitching style once his velocity starts to decline with age.

We can't be sure that this mechanical quirk is the root of all evil, but there's a decent chance that it could be. As he works on fine-tuning the new delivery, there are bound to be some off days. The fact that Verlander can do something like this in the middle of his career and still pitch as well as he has is testament to how amazing of a pitcher and athlete he is.

This is something that I may look deeper into once I have the time, but between my sudden outburst in last night's recap thread and on Twitter, I had to put something together to share my findings.

What do you think? Is this the issue we have been looking for, or are we still grasping at straws here?