What the heck is wrong with J.A. Happ?

The Yankees signed J.A. Happ to a two-year, $34 million deal—complete with a third year $17 million vesting option—with the hope that he could replicate his stellar performance down the stretch last season. After the Yankees acquired Happ from the Blue Jays at the trade deadline, he went 7-0 with a 2.69 ERA and proved he had plenty left in the tank at age-35. At least it appeared that way. Happ has struggled in 2019 to the tune of a 5.23 ERA in 16 starts.

So what’s going on with Happ since he re-signed in New York?

Diminished velocity

The veteran left-hander has never been a pitcher that blows batters away with a high-90s fastball or a breaking ball with a high spin-rate. He did, however, have a mastery of his pitch arsenal and posted above-average strikeout totals the past two seasons, with an 8.79 K/9 in 2017 and a 9.78 K/9 in 2018.

Unfortunately, Happ’s stuff has diminished a bit this season. According to FanGraphs, his fastball velocity is down from 92.7 mph in 2018 to 91.8 mph in 2019, and his slider velocity dropped from 85.7 mph to 84.4 mph. Even with lower velocity, he’s getting more vertical movement on his slider, and the results have been solid. Opponents, however, are taking advantage of his fastball, a pitch that was his greatest weapon last season.

Happ has already given up 15 home runs off his fourseam fastball this season, after surrendering 18 all of last season on three times as many pitches. With diminished velocity, there’s a smaller margin for error. He’ll need to figure out his formerly reliable fastball if he’s going to be effective moving forward.

Struggles against left-handed batters

Last season Happ proved a nightmare for lefties. They combined to slash .171/.239/.248 against him in 2018, but that jumped to .300/.349/.475 thus far in 2019. Happ has a reputation as an effective fly-ball pitcher, but he’s having trouble getting left-handed bats to hit the ball in the air at the same rate he did when he first came over to New York.

Right handed batters have a fly-ball percentage of 47.5 against Happ this year, compared to 45.3% last season, but left-handed batters are hitting fly balls on only 22.4% of batted balls this season, compared to 30.4% last season. Happ previously had trouble getting lefties to fly out at the same rate as right-handed batters, but it seemed to be a successful recipe until now.

Susceptible to the long ball

Even though Happ is getting right-handed batters to hit the ball in the air at his normal rate, there’s been a big spike in hard contact. Righties made hard contact on 34.1% of batted balls against Happ last season, and that number has significantly jumped up to 42.7% in 2019. The result of all this? Happ has the highest HR/FB and HR/9 rates of his career, and his ERA is the highest it’s been since 2012. In fact, Happ sits at fourth worst in MLB with 1.90 HR/9, behind only Reynaldo Lopez, Mike Leake, and Dylan Bundy.

Pitch mix

In order for Happ to get his season–and Yankees future–back on track, he might look to adjust his pitch mix. Don’t blame Happ’s struggles on the Yankees pushing increased slider usage. It’s true that he’s throwing his slider more this season (16.3% in 2019, 12.7 in 2018), but opponents own a .218 xBA and 86.8 mph exit velocity against his slider, the lowest of any of his pitches.

He’s also traded in his fastball for more sinkers, which could be something he looks to change to get back on track. He’s throwing fourseam fastballs 12.1% less than last season and sinkers 8.7% more. Opponents own a .294 xBA against his sinker, so it’s worth considering if Happ should abandon his sinker at times and use his fastball more often, even with a little less zip on it.

Major league batters have never hit home runs at a higher rate, and the Yankees have to be at least a bit concerned that they signed an aging fly-ball pitcher at the wrong time. Happ’s been around the big leagues for 12 years, long enough to understand the importance of making the proper adjustments, but he’s got his work cut out for him if he’s going to be an asset in the second half of this season and beyond.