Chris Archer Has a Four-Seamer Problem
The Chris Archer narrative is this: Once upon a time in Tampa Bay, he was a good pitcher. He struck out many batters. Then the Rays traded him to Pittsburgh, where the Pirates’ pitching coaches forced him to develop a sinker. Doing so made him ineffective and resulted in the 5.19 ERA and the terrible peripherals he put up in 2019.
Luckily for Archer, he made the decision to ditch his sinker –– on July 12th, to be exact. After that date, not a single sinker. His FIP in his remaining starts was 3.29, good for 13th out of 143 qualified pitchers.
So when Archer reunited with the Rays on a 1 year, $6.5 million, he seemed cognizant of the fact that his sinker contributed to his struggles in Pittsburgh. As if to proclaim that, moving forward, he would improve himself as a pitcher, Archer told the media of his intent to officially abandon the sinker:
Good for him! An issue with this narrative, though, is that it overlooks multiple issues with Archer’s four-seamer. It’s not that the pitch is in decline, but rather that it’s medicore by modern standards. In 2017, the pitch recorded an xwOBA of .381. In 2018, .399, and in 2019, .384. Over the three-year span, the pitch’s SwStr% has fallen from 8.6% to 7.2%. The decreasing rate of whiffs are a red flag, but overall the pitch hasn’t become particularly worse or better, at least results-wise. It’s just… not very good.
For a while, Archer was able to get away with an unrefined fastball. One reason why is velocity –– his four-seamer sat 95 to 96 mph years back, when the league average velocity was a few ticks below what it is now. Since then, pitchers have evovled to average 93.3 mph in 2020. In contrast, Archer’s own velocity took a nosedive in 2019:
Moreover, the overall trend shows a gradual decline in velocity. There are always fluctuations, but it’s clear that Archer is now incapable of touching 96 mph, possibly even 95. A once competitive edge has become moot. Again, this development isn’t detrimental at the moment, but if it continues it’s hard to imagine Archer ever re-reaching former levels of performance.
Other issues are more subtle. Another reason why Archer could rely on his fastball was due the pitch’s solid vertical movement (i.e. ride), which helps induce whiffs in the upper part of the zone. Archer doesn’t live up there –– in fact, he prefers to locate down the middle, another issue the Rays should address –– but help is help is nonetheless.
But over the past few seasons, his four-seamer’s vertical movement is also trending downwards:
In baseball, diagnosing a symptom is easy, but identifying the factors behind is more difficult. A drop in vertical movement could be tied to velocity, or it could be a mechanical issue. Without more granular, often proprietary data, it’s hard to draw conclusion about pitchers’ ailments. What’s worth exploring, however, is the change in Archer’s vertical release points by month:
This time, I’m more intrigued by the month-to-month changes than the year-to-year changes, which at first glance don’t reveal a difference. But zooming in, we can notice that for the past two years, Archer’s vertical release point began on a high note, only to drop back down by around 0.2 feet by season’s end. What gives? There’s not much information online. Maybe it’s a manifestation of Archer’s struggles to find his former self.
The way Archer is tinkering with his release point, though, isn’t going to do him much favors. We know that vertical release point is correlated with positive vertical movement –– save for outliers like Hader –– so it makes sense to attribute Archer’s worsening fastball to inconsistent release points. If there’s a silver lining, it’s that a lower release point does lead to a flatter Vertical Approach Angle, or VAA, which research has shown to increase effectiveness up in the zone. I suppose it’s up to the Rays to find the optimal mid-point between vertical movement and VAA. Easier said than done!
One last point. We’ve looked at velocity, vertical movement, and vertical release point, and how each has an effect on Archer’s fastball. But the most confusing development of them of all has to be out-of-nowhere horiztonal movement. What the heck happened between 2018 and 2019?
Unlike with vertical movement, release point has no meaningful relationship with horizontal movement. So here’s what I’m thinking: spin direction. Good four-seamers have a spin directions of around 12:30 –– a perfect 12:00 is impossible –– which maximizes vertical carry through back spin and minimizes other types of spin. Verlander’s fastball is a great example. And courtesy of Rapsodo, here’s a visualization of which spin directions generate different types of spin:
Imagine that, due to a change in grip, Archer’s spin direction on his fastball changed –– from one prioritizing backspin to a different one that introduced sidespin. In 2019, the decrease in vertical movement occured in tandem with an increase in horizontal movement. The evidence lines up. Perhaps the detrimental effects of Archer’s sinker aren’t just limited to batted ball damage, but also how it influenced his four-seamer. Could it be that Archer unknowingly began gripping his four-seamer more like a sinker, whose spin direction is around 1:30 instead?
By signing Archer, the Rays seem confident in their ability to re-tool his four-seamer. Restore the release point, fix the spin direction, focus on ramping up velocity. With enough effort, there’s a fantastic pitcher waiting to erupt.
But that’s all a maybe. Just because Archer is ditching his sinker doesn’t mean he’ll automatically return to form –– there’s work remaining, work that we’re not sure will pay dividends. Sure, the sinker is terrible (.522 xwOBA in 2019, barf), but Archer has a four-seamer problem, too. It’s a bit more complicated than one bad pitch.
All data courtesy of Baseball Savant, Brooks Baseball, and FanGraphs.
