Monday, May 03, 2010

Liriano's rubber shifting

In the bottom of the third inning of Sunday's game against the Indians, Fox Sports North commentator and former All Star pitcher Bert Blyleven appeared mystified by what he thought was a new finding: Francisco Liriano was switching his location on the rubber contingent on whether the hitter was left- or right-handed.

During Shin Soo Choo’s at-bat, Blyleven released this nugget: “To be honest with you,” Blyleven confided with the viewers in the third, “I’ve never seen Liriano going to that first base side of the pitching rubber. He’s usually on the third base side…maybe he’s shifting with left-handers and right-handers…we’ll keep an eye on that.”

Following Choo was the right-handed hitting Austin Kearns. Blyleven then noted that “now Liriano, with a right-hander up, you see he’s moving on the pitching rubber…”

“How about that?” Interjected Dick Bremer.

“…over to the third base side.” Blyleven allowed a pitch to pass then added, “You don’t see that too often where a pitcher will move one side [of the rubber] to the other.”

In the ensuing bottom half of the fourth the broadcast threw up a split-screen graphic depicting Liriano’s approach to the left and right-side of the lineup. This was followed by Blyleven’s admission “I didn’t notice that in the other starts for Liriano…maybe it’s something he and Rick Anderson, the pitching coach, have been working on.”

Congratulations. Blyleven may have stumbled upon a discovery that has been an occurrence for the southpaw since '08. According to pitch F/X charts, Liriano has used this approach dating back to his return from Tommy John surgery:

In ’08, Liriano’s release points varied from slight over a half-foot to two-and-a-half feet to lefties but ranged from dead-center to slightly under two-feet to righties. Meanwhile, in this past season, there was stronger visual evidence of this shift:

Last year, Liriano worked the lefties from well-over the half-foot mark to almost three feet away from the middle of the plate. This shows more of a movement down the rubber towards the first base side in the event of left-handed foes. Likewise, his approach to righties were the same as his '08 year -- in spite of some very unfavorable results. Essentially, he kept his positioning static on the third base side and had a release point between dead-center and two-feet to the left of the plate. Here is video evidence of Liriano working to lefties on the first base side then to righties on the third base side in ’09.
As pitch F/X shows in 2010, all of his release points to lefties have been at a foot-and-a-half to two-and-a-half feet to lefties. Instead of working from the middle of the rubber like he had in the past to some lefties, he is consistently staying at the first base side. This has worked extremely well for Liriano as lefties were hitting 2-for-23 (.087) against him in his four starts heading into Sunday’s game. 

So for the past two seasons (possibly longer if we could find reliable '06 data or video), Liriano has transitioned up and down the rubber. This is hardly a new development and definitely not something Anderson and him have concocted this season. Still, in Blyleven's defense, while Liriano at times worked lefties from the middle of the rubber in the previous two seasons, this year he has remained consistently on the far left-hand side of the rubber. 

This emphasis may have made him that much more unhittable to same-sided batters as Liriano's ground ball rate has skyrocketed in this young season comparative the the past two:

Liriano vs LHB:GB%OPS

Despite what Blyleven would levy on air, Liriano has been moving up and down the rubber regularly since ’08. What is different in 2010 is that he appears to be moving to the first base side against ALL lefties and has avoided pitching from the middle as he did in the previous two seasons, which is working extremely well for him so far.

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