CC Sabathia's changeup has the potential to be deadly again

After a short stint on the disabled list, CC Sabathia is slated to make his start against the Oakland A's on Friday. He will enter the game with a 3.81 ERA in 28.1 innings, all spread over five starts. A lot has been made of his new cutter, which he has used to keep right-handed hitters in check so far. Yet one of the more interesting developments has been his revamped changeup, which was on display during his last start against the Orioles.

According to Brooks Baseball, CC threw 21 changeups against the O's, generating swinging strikes on 8 of them. He even got early-season MVP candidate Manny Machado swinging on a changeup down and away:

Over the past few years, CC's once-dangerous changeup was no longer a real weapon for the imposing southpaw. As his fastball velocity began to decrease, the effectiveness of his changeup also suffered. During the 2013 and 2014 seasons, his change had a Whiff/Swing ratio under 30%, with hitters batting .279 with a .475 slugging percentage against the pitch.

In terms of generating whiffs, his changeup continued to be mediocre in 2015, until he started to get more movement, seemingly out of the blue. Here are Pitch F/X's readings for the vertical movement on his changeup over his career with the Yankees:

Starting with his July 30^th start against the Texas Rangers, he got as much as three more inches of vertical drop on his changeup. Since that game, his changeup's Whiff/Swing ratio is back up to 43.4%, which puts him in the same category as pitchers like Felix Hernandez and Cole Hamels if he can keep it up.

It is tough to say how this improvement came about, but an obvious guess is that he tweaked his grip. Within the category of offspeed pitches, most can be described as splitters or circle changeups. Some pitchers like Danny Salazar and Kevin Gausman are described as throwing a hybrid pitch called a split-change.

Like fastballs, circle changeups (non-splitter offspeed pitches may be a more accurate description) can be thrown with a four-seam grip or a two-seam grip. Last season, Jeff Sullivan at FanGraphs noted that Cardinals flamethrower Carlos Martinez switched to a two-seam grip, getting more drop and tailing action, in addition to vastly superior results.

Since CC has added downward movement to his changeup, it is possible that he switched from a four-seam grip to a two-seam grip. This picture from the Yankees' media day in 2011 appears to show CC using a four-seam grip on his changeup:

If CC can reestablish his changeup as a weapon against right-handed hitters, it would give him another option besides his new cutter. Even during the height of his struggles on the mound, he was still a force to be reckoned with against lefties. On Friday, he will face an A's lineup that consists of power hitting righties like Khris Davis, Marcus Semien, and Danny Valencia. In addition to the cutter, look for CC's changeup to be on display when he returns to his hometown.

Data is courtesy of Fangraphs and Brooks Baseball.