Why J.A. Happ struggled against the Red Sox

The Yankees acquired J.A. Happ for one big reason: to beat the Red Sox. In 2018, Happ went 1-1 against Boston with a 1.99 ERA to go along with an excellent 29-6 K-BB ratio in 22.2 innings. For his entire career, he’s 8-4 against Boston. For whatever reason, it seems like the Red Sox do not like to face the left-hander.

Happ, hopwever, bombed in Game One of the ALDS, his biggest start of the season. He went just two innings and allowed five earned runs, taking the loss. But why did Happ suddenly lose effectiveness after a 7-0 run in 11 starts as a Yankee?

The 35-year-old threw over 70 percent fastballs against the Red Sox, but that’s not an issue. Happ always throws a lot of four-seamers. The real problem was where he left them. Happ’s pitch location against the Red Sox in Game One looked nothing like the pitch location he had his success with earlier this year. Consider this heat map as a Yankee during the regular season:

There’s a lot of red up and in on that graph. That’s a dangerous recipe against powerful lineups like Boston’s, but Happ makes his living that way. He excels when he challenges hitters and keeps them off balance by working quickly and pounding them inside with heat.

Oddly enough though, Happ avoided the inside corner for much of his playoff start, instead nibbling down and away:

Unsurprisingly, Happ didn’t generate many whiffs with those locations. He only garnered three swings and misses all night, and just two strikeouts. Most of those whiffs were on high fastballs, as is his forte.

Happ did accomplish his game plan against some hitters. Take his game-opening strikeout of Mookie Betts on a high and tight fastball for example:

Or this jam sandwich on Xander Bogaerts that resulted in a feeble pop-up:

Happ’s up-and-in heater did work at times against Boston. Unfortunately, the Red Sox feasted on everything else that Happ offered. I’m thinking of this hanging slider against Andrew Benintendi that resulted in a base hit:

Happ’s lucky that that was just a single. Seeing that it wasn’t working, Happ scrapped the slider early, only throwing three of them all game long. The two biggest hits he gave up all night though, the J.D. Martinez home run and a Betts double, were on fastballs.

Those pitches are down and in. One of them is even out of the zone! However, those are the pitches that the Red Sox do the most damage against. Their hitters love to dig fastballs or curveballs out of the dirt and take aim for the Green Monster. If Happ faces the Red Sox again, he cannot keep throwing them low fastballs, or else they’ll keep golfing them over the Monster.

Happ was close to walking the tightrope out of trouble on Friday night. When he was sticking with his bread and butter, throwing up and in, the Red Sox didn’t do much. What got him into trouble though, was his lack of offspeed command with both his slider and changeup, and his mistake of throwing the Red Sox the pitch they love most: fastballs they can lift to the Monster. For Happ to succeed against the Red Sox next time, he’ll need to be extra careful with his location.