Nick Robertson is back with the Red Sox with a new sweeper

Boston has called Robertson back up to the major-league roster.

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Nick Robertson is back with the Red Sox, an intriguing pickup from the Dodgers in the Kiké Hernandez deal along with Justin Hagenman. His changeup is what immediately garnered traction on Twitter, given its near 25 SwStr% on the pitch in 27 outings for Triple-A Oklahoma City while thriving with LA’s affiliate. The 26-year-old authored a 2.54 ERA and a 13.3 K/9 and got a big-league look right away when he got to Boston. 

The righty let up four runs in four innings across his two outings though, and struggled without any real third pitch. When he was acquired, I wrote that a third pitch would be necessary for him to have success; he had a third pitch — but he rarely used it. It was a gyro slider with ~5" of sweep at ~86, which overall was not the most effective pitch; hence, he didn’t use it all that often (less than 10%). His older scouting reports described him as a three-pitch arm that used the slider against righties and the changeup against lefties but when he got to Triple-A he barely touched his slider. 

I suggested adding a gyro cutter (1–2" of horz. movement) with a bit more speed on it which would have basically been a slider tweak given that his previous slider could have already been considered a cutter. But the WooSox seem to have taken Robertson the opposite route — and now he’s back with Boston. From the looks of it they’ve given Robertson a sweeper with ~12" of sweep — even getting as much as 20" of sweep on some pitches  at a similar ~-7.5° VAA and ~86 mph as the slider, but the new sweeper is also getting some decent life on it at ~5" of ride compared to the slider’s ~2” of carry.

It gives him something to play with horizontally and take care of righties better with, and he’s used it more than he usually used the slider given that it’s a much better pitch shape than his previous slider. In essence, it’s really just a slider tweak given that the only real change was the horizontal movement—but still one that can pay dividends for him.

His fastball on the other hand gets a nice ~16" of ride at 94–96 along with a mid-4° VAA and 7–8" of run. It has just 2100 RPM range of spin though, which is fairly low — and the pitch doesn’t get nearly as much love from Stuff+ as something of with that caliber of ride+velocity usually gets — only an ~80 Stuff+ on FanGraphs and high-90s on Pitch Profiler; the changeup however gets a nice ~15" of arm-side run at 86, getting around a 100 Stuff+ on both models. The old slider got a ~110 Stuff+ while being rarely used, but we can’t get the Stuff+ numbers on the new sweeper until he makes an appearance with it.