The above GIF came together from last Sunday's performance against the Blue Jays. In that game, Michael Pineda induced 12 ground balls and 2 fly balls, a stark difference between the batted ball rates he put up with the Mariners in 2011.
Throughout the broadcast, and other broadcasts during Pineda's starts, David Cone and the rest of the booth talked about how the pitcher was still having trouble locating his fastball. Cone called it cutting the fastball, meaning he was holding on to it a little too long, and thus the ball was flying in toward left-hand hitters. The movement on his fastballs did look to change at times, and his command was likewise spotty when it would show the cutter action.
We know that in 2011, Pineda threw primarily a four-seam fastball and a slider. Occasionally, PITCHf/x picked up on movement that looked like a two-seam fastball/sinker and a cutter. Pineda used the four-seam fastball and slider combination 90.2% of the time, and this resulted in a 44.8% fly ball rate, and a 36.3% ground ball rate. Though his strikeout approach at such a young age was promising, his high fly ball ratios were a big red flag for a pitcher coming over to Yankee Stadium and the rest of the AL East.
Now it looks like Pineda has corrected some of these fly ball problems. His pitch movement looks to have more horizontal movement than your typical straight four-seam fastball, and the GIF above shows the variation. Though it's impossible to tell if he's doing this on purpose, Pineda now has a track record of success generating ground balls and weak contact this month. Be it a cutter or sinker, it looks like Pineda has experimented with a few new pitches. Obviously the two pitches have opposite movement, with the cutter moving in to left-handed hitters, and the sinker into right-handed hitters, but it's hard to tell if perhaps his four-seam fastball looks like a cutter due to adding a sinker, or perhaps his four-seam looks like a two-seamer due to adding the cutter.
Unfortunately, due to the stadiums they've played in, we have no idea what actual pitches he's throwing yet. Once Pineda gets his first start in the Rogers Center, we'll have PITCHf/x cameras to give us a better idea of the different movement he's generating, which will help us place his fastballs on the subjective pitch type spectrum we all love to use.
Adding these pitches was a necessity, as he can no longer live on a high-90's fastball with his shoulder history. Even if he could survive the next few years with a high velocity four-seam fastball, fly balls are bad news in Yankee Stadium. By becoming more of a ground ball contact pitcher with a lower velocity fastball, Pineda will ultimately reduce some of his flashy upside, but it should theoretically help his chances at staying healthy and succeeding in a new hitter friendly ballpark.