Early on this season, Rick Porcello looked like the Cy Young award winning pitcher that was on display in 2016. He was absolutely dominant, routinely working deep into games and giving the Red Sox a very high chance of winning with his pitching performance. In his last two games, however, he has seemed to regress a bit and has more resembled the disappointing-type pitcher that he was last year.
Over his first 7 starts, Porcello was arguably Boston’s best starter, posting a 2.14 ERA and a 0.82 WHIP. He was holding opposing hitters to a .193/.225/.269 slash line and a .252 BABIP, and perhaps the most impressive stat that he posted was his 78% LOB percentage. He was getting guys out in all situations, bases empty, runners on base, in high leverage situations, in hitter’s counts, in pitcher’s counts, etc. Everything seemed to be working for him.
In his two starts since then, though, Porcello’s numbers have fallen way back towards, and even below, the mean. Versus the Yankees on 5/9 and Oakland yesterday, he pitched a combined 11.1 innings, allowing 10 runs on 17 hits. That’s good for a 7.94 ERA and a 1.76 WHIP. Opponents hit .347/.396/.617 against him in that span with a .385 BABIP, and he’s allowed almost 40% of baserunners to reach home. That’s a huge regression, but what caused it?
One common cause for something like this could be a dip in velocity or pitch movement, but Porcello’s average velocities for all of his pitches match up almost exactly from the beginning of the year to now, and his pitch movement is actually a little better of late than earlier on.
The only significant change in his game over his last two appearances that could explain his dip in production has been the amount of strikes he’s thrown.
In his first 7 starts he was throwing 68.5% of his pitches for strikes. In his last two starts, though, he’s down to a 58% strike rate. This has led to a decrease in both swings on pitches out of the zone (34.5% in his first 7 vs. 25% in his last 2) and swinging strikes (9.4% vs. 8%). It’s clear that his dip in strike percentage has allowed hitters, now knowing that Porcello is struggling a bit to find the zone, to sit and wait for pitches over the plate, leading to more solid contact being made (36.6% in his last two vs. 27.2% in his first 7).
It’s a small sample size, though, and there’s nothing pointing towards this short span of difficulty continuing into the future, let alone for the rest of the season. Based on the eye test alone, Porcello seems to be more comfortable on the mound than last year, and it would be unfair to assume anything from him other than solid work going forward.