I wanted to follow up David's post from yesterday with some GIFs highlighting Xavier Cedeno's changing arm slot. If you didn't catch David's Three Astros Things yesterday, he linked to a Beyond the Box Score article that presented some interesting data about pitchers who change their arm slot depending on the handedness of the batter. Cedeno took center stage as one of the relievers with the more extreme changes in arm slot.
I went and grabbed some footage from Cedeno's most recent appearance in the World Baseball Classic to show the change in arm slot. I was fortunate that he struck out both a left-handed hitter and a right-handed hitter as it makes a better GIF.
Sidearm vs. Left-Handed Batter
I'm not an exactly an expert at identifying pitches but that looks like a slider to me.
Over the top vs Right-Handed Batter
That pitch looks like a curveball. It can be hard to tell the different arm angles at first but that's the beauty of GIFs, they continuously repeat.
Prior to signing with the Astros before the 2011 season, Cedeno posted about six strikeouts per nine innings (SO/9) and a walk rate around four per nine innings (BB/9) in the Colorado Rockies minor league system. After a year in independent ball, in 2010, Cedeno signed with Houston and so far has posted 8-9 SO/9 and a 2.9-3.5 BB/9 in between AA and AAA. The question was brought up, and remains: Has Cedeno found success because of the adoption of different arm angles depending on the batters handiness? It's safe to assume that this would be the case; unfortunately, I can't get the footage to confirm because he never made a major league appearance prior to signing with the Astros. I have been told by Mike Fast that Cedeno has in fact been using different arm angles since AA in 2011 so that clarifies one part of the puzzle.
I want to look at another lefty I've seen use this strategy with outstanding success: Michael Roth.
In 354 college innings for South Carolina, Roth had a 1.91 ERA, 268 strikeouts, 105 walks and quite possibly one the most successful College World Series runs for a pitcher in history. He was drafted in the ninth round of the 2012 MLB Draft by the Los Angeles Angels of Anaheim. In 22 minor league innings, Roth has a 4.91 ERA, but more noteworthy is his 8.6 SO/9 and his 4.5 BB/9. Roth may never make it out of the minor leagues, but that strikeout rate for a soft-tossing lefty is interesting.
Roth employees a similar change in arm angle as Cedeno.
Sidearm vs Left-Handed Batters:
Over the top vs. Right-Handed Batters
Cedeno's recent success makes Roth a slightly more interesting pitcher to follow. In my profile of Roth last May, I noted that Roth will need to work on his command. If he does that, he may ends up like Cedeno, who still has his own trail to blaze. Another thing that I noted in the profile is that Roth is a lot like Dallas Keuchel and that got me to wondering what Keuchel's release point is vs. right-handed and left-handed batters was and if he should employee a similar strategy to Cedeno's.
Keuchel vs. Right-Handed Batters
Keuchel vs. Left-Handed Batters
Keuchel uses the three-quarter arm angle which is not what Cedeno or Roth are doing. Could employing a similar arm angle strategy as Cedeno improve Keuchel's strikeout rate?
Wesley Wright is a straight side arming reliever against all batters: left-handed batters had a .538 OPS against him last year; right-handed batters fared much better with a .790 OPS against. It would seem that to optimize a left-handed pitcher, have them sidearm against left-handed batters and go over the top against right-handed batters.
Wesley Wright's 2012 release point against all batters
I remember one of the announcers, I think it was Orel Hershiser, discussing Roth's different arm angles during the College World Series wondering why more pitchers don't vary their arm angles depending on the batters handedess. It's an interesting question and one that might not be easy to answer.
For Keuchel to employ the strategy, it would mean changing everything he's done since college and most likely beyond.
As Jon Roegele in the Beyond the Boxscore article noted, there is also an injury concern as most of the pitchers who changed arm angles have spent some time on the disabled list. Maybe that explains why it hasn't been employed by more pitchers or maybe it only works as a reliever. I don't even know if Roth is still varying his arm angles based on the batter at the plate or if the Angels have had him change it. I would assume that he is still based on the strikeout rate but I can't say for certain.
Keep in mind that we've only looked at a few examples and we need more data for anything certain but this is certainly something we'll have to revisit later in the regular season.