Yesterday, Marco Estrada told Todd Rosiak of the Journal-Sentinel that the problem in his Sunday start in which he allowed 4 earned runs in 5 innings was his changeup:
Estrada: "Plain and simple, I’ve got to fix the changeup because without it I’m going to get hit around just like I did today."— Todd Rosiak (@Todd_Rosiak) May 18, 2014
More Estrada/changeup: "I think it’s my best pitch and normally when I don’t have it I can bounce back from it pretty quick."— Todd Rosiak (@Todd_Rosiak) May 18, 2014
Can we pick up anything about what was going on?
Most pitchers have about a 8-10 mph gap between their fastball and changeup. If that gap gets too small, hitters can time it about the same as a fastball, and it tends to lose effectiveness. If the gap gets too wide, the changeup is easier to identify and since it does not have the movement of other breaking pitches it's essentially just a slow "fastball". What I think has made Estrada's changeup a pretty effective pitch in his breakthrough as solid major league starting pitcher is that his gap is generally on the wider side, around 12 mph.
That gap wasn't much different on Sunday. Marco threw 54 fastballs that averaged 90.4 mph out of his hand, and 22 changeups that averaged 78.3.
More interesting is Estrada's general pattern of pitch usage. His pitch usage varies much more from game to game than most pitchers. For example, in his start against Arizona on 5/6, only 11% of the pitches he threw were changeups. Against Philadelphia on 4/10, that number was 42%. On might think that the source of this variation has a lot to do with facing lefty-heavy vs. righty-heavy lineups, as pitchers tend to rely on a changeup much more frequently against opposite-handed batters. That is true to some extent, but even so Estrada's percentage of changeups thrown against righties has varied from 10% (5/6) to 33% (4/26).
Sometimes, in the realm of pitch analysis, it's easy to overthink things. Here is Estrada's at-bat to Wellington Castillo that ended up well over the fence, courtesy of the Brooks Baseball Pitch f/x tool (catcher's perspective):
That, my friends, is a changeup at the belt, and given the wide velocity gap, is a 78 mph slowball out over the plate. With a fastball/changeup gap as wide as Estrada's, he needs to get the pitch down and let it move to be effective. Most major league hitters are going to do quite a bit of damage to that pitch if they're given time to recognize it.
However, it looks to me like there is nothing systematically different about Estrada's changeup, and he just made a few mistakes with it on Sunday. Mike Olt's home run came on a low fastball, but there were other instances of changeups up in the zone being hit hard. Sunday's start was an across the board poor performance for Marco, but there is no reason at this point to think there is anything wrong beyond it just being a day in which he couldn't throw the pitch where he wanted it. In baseball, unfortunately, that happens sometimes.