Can J.A. Happ remain an effective starter for the Yankees?

Last year’s ALDS loss highlighted the Yankees’ need for starting pitching help. Brian Cashman almost immediately addressed that by trading for lefty James Paxton early in the offseason. It was clear, however, that Cashman wasn’t done. He wanted to add two quality starters to the rotation by spring training.

The second starter turned out to not be Patrick Corbin, but instead a returning J.A. Happ. The veteran agreed to a two-year, $34 million deal with an option on a third year if Happ reaches 165 innings or 27 starts in 2020.

Happ certainly doesn’t have the same star power as Corbin, but is a far less expensive option — which the Yankees value a lot lately — with an established ability to succeed in the Bronx, as his 163 ERA+ in pinstripes illustrates. Happ was solid for the Yanks in his 63.2 innings of work, but how will the 36-year-old fare over the next two seasons?

One negative reaction to the Happ signing was the age, and how a six-year deal for Corbin would end at the age Happ is today. The Yankees, however, elected to take the more financially safe move. To be fair, they didn’t settle on trying Domingo German in the rotation again. Happ is proven to be a solid pitcher, but the concern is whether that can continue as he approaches 40.

Happ’s ability to get outs at this stage in his career is widely credited to his high spin rate, particularly on his fastball, which saw a spike in usage in 2018. Happ threw his fastball 59.3 percent of the time last season, compared to 43 percent in 2017. His fastball remained around the same in terms of velocity (92.3 mph) as it has over the past three seasons, but his hard hit percentage against the fastball went down.

Due to the success of his fastball, he threw his sinker significantly less than he did last year. With an average spin rate of 2,334 rpm on his fastball, Happ finds himself around the top 20 in the league among starters. Combining a spin rate like that and above average control means a 92 mph fastball can feel more like 95 to opposing hitters. That spin rate, however, has been slowly but surely dropping in recent years.

Happ’s 2.6 BB/9 certainly helps with a declining spin rate. As pitching minds like Greg Maddux have explained, location is top priority. However, a decreasing spin rate for a fastball-heavy pitcher like Happ leaves less room for error. His sinker saw a more rapid decline in spin rate, which could account for its decreased usage in 2018.

With this in mind, there is certainly a reason to be concerned about Happ’s production moving forward, as their is with almost any other starter who signs a multi-year deal after his 35th birthday. We’ve seen lefties, specifically on the Yankees, reinvent themselves and enjoy productive ends to their careers (hello CC Sabathia and Andy Pettitte). If Happ’s current spin rate trends continues, the Yankees would need him to follow a similar path.