Masahiro Tanaka could be better than ever in 2017

After signing Masahiro Tanaka in 2014, Brian Cashman was quick to temper expectations surrounding the Japanese phenom, saying that while Tanaka had “a great deal of ability,” he had him projected as a number two or number three starter. Tanaka wasted no time reaching his ace ceiling, with a 2.77 ERA in an injury-shortened season. In 2015, Tanaka took a step back, with a 3.51 ERA, a figure that was propped up by a bad habit of giving up too many home runs.

Last year, Tanaka returned to his ace-like form. He had a 3.07 ERA in just under 200 innings, also finishing seventh in the AL Cy Young voting. A major part of his resurgence, as well as his ability to keep the ball in the yard, was his improved fastball and sinker. In September, Jeff Sullivan at FanGraphs noted that Tanaka was doing a better job of locating both pitches, which helped him limit the number of home runs he allowed.

Where his fastball and sinker improved though, Tanaka’s once-deadly slider took a step back. In 2014 and 2015, hitters put up a .459 and .450 OPS against his slider, respectively. In 2016, they had a .727 OPS against Tanaka’s breaking ball, with 10 of the 22 home runs Tanaka allowed coming off the slider.

According to Pitch F/X, Tanaka has not been getting as much vertical movement on his slider. Keep in mind that a lower value for vertical movement means more drop:

Tanaka also hasn’t been getting as much horizontal movement. As a right-hander, a higher value for horizontal movement means more cutting action:

In 2016, Tanaka’s splitter was as dangerous as ever. Looking ahead to 2017, it appears that he has found a way to limit hitters’ damage against the fastball. His elbow flared up again at the end of the 2016 season, but there is currently no reason to believe that it is a serious injury. If he can reclaim his once-dominant slider, we could see Tanaka return to the level he was at before he got hurt in 2014.

As a pitcher for the New York Yankees, an inconsistent slider is not the worst problem to have, either. If there is one thing Larry Rothschild knows, it is how to fix a broken slider. For example, CC Sabathia’s slider was mediocre in 2014 and 2015, but hitters were held to a .529 OPS against it in 2016. Adam Warren directly credited Rothschild with helping him regain a feel for his slider after he was traded back from the Cubs, according to a report from Kenny Ducey at Baseball Prospectus.

Masahiro Tanaka has never given anyone a reason to question his motivation. But for what it’s worth, he has the option to become a free agent after the 2017 season. With his four main pitches running on all cylinders, his health is the only thing keeping him away from being a Cy Young candidate.

Data is courtesy of FanGraphs. Charts are courtesy of Brooks Baseball.