The Yankees need David Robertson to be dominant again

This post should be prefaced with an important note: David Robertson is not having a bad year. He opened the season by giving up a grand slam to Justin Smoak, which immediately ballooned his ERA. He also struggled through a sub-par May (when he posted a 5.56 ERA), but has responded by posting a 2.08 ERA since, including an opponents’ slugging percentage of just .318.

Still, Robertson has shown some troubling flashes that Yankees fans aren’t used to seeing out of him. He returned to the Bronx prior to the trade deadline last season and gave the Yanks a reminder of what they had been missing for the past three seasons, including a number of clutch performances in October. This year he has not shown the same dominance. The Yankees need 2017 Robertson to help anchor their deep bullpen while Aroldis Chapman recovers from his knee injury, and while arms like Chad Green and Tommy Kahnle look to find their own 2017 versions of themselves.

Even with Robertson’s struggles in May in terms of ERA, his ground ball percentage was still just below 50 percent, which is in line with his career norm. However, that percentage dropped 15 percent over the next two months. That drop off in ground balls has caused an alarming uptick in balls leaving the park, especially recently.

Robertson allowed just three home runs in his first 45.1 innings this season, but has allowed the same amount in his last 10.2 innings, including a home run in Friday night’s win over the Orioles. His HR/9 through the first half of the season was 0.62, but that number has jumped to 2.19 so far in the second half. Given Robertson’s role in the late innings, those home runs have been coming at crippling moments in the game, especially when the Yankees’ shorthanded offense doesn’t have all of their weapons to mount a comeback. Fortunately, they were able to do so on Friday night, but not all teams will be as bad as the Orioles.

We’ve seen Robertson at his best at times lately, but not with the same consistency. His strikeouts per nine are up from the first half of the season, and his walks per nine are down. However, he has gotten into trouble when hitters make contact. The spike in home runs allowed has caused his FIP to rise almost two full runs in the second half of the season, and his hard contact percentage allowed has inflated from 29 to 46.7 percent. These are all numbers that Robertson needs to improve upon down the stretch of the season, as the Yanks look to secure a postseason berth.

Again, by no means has Robertson been awful this season. He does need to address his recent struggles with the long ball, though, and get back to being the ace setup man that delivered moments like this: