Starting Pitcher Fastball Velocity Gainers — Apr 8, 2021, A Review

Today, I complete my review of the early starting pitcher velocity changes to see how whether it was an early sign of what their velocities will be over the rest of the season. We’ll finish our reviews up with another set of velocity gainers.

This was a pretty good group of pitchers who held onto most of their first start velocity gains to still post a significantly higher mark over the rest of the season. Six pitchers held onto the majority of their gains, while one never made it that far due to injury and only made that one start.

Not only did Carlos Rodon enjoy a velocity spike during his first start, but he maintained it all season. He ended up posting what was easily a career best velocity mark, a full two miles per hour higher than his previous career high. This was huge, because Rodon has missed significant time to injury over the years, having only recorded 40.1 innings since 2019. Turns out, he may have been the absolute best argument for why first start velocity matters a whole lot. If you solely picked him up or traded for him based on the velocity surge during that first start, you rode one of the season’s biggest breakouts all year and were quite the happy one.

This was merely a partial rebound for Mike Foltynewicz, whose velocity dove in 2020. It didn’t quite rebound fully though, as 2021 still marked the second lowest velocity of his career. It didn’t matter though, as his strikeout rate still fell to a career low.

Nick Pivetta nearly held onto all his velocity gains the rest of the year, losing just 0.2 MPH. Similar to Folty above, this was merely a rebound off a sudden collapse in velocity last year, so this brought him right back to where he usually stood. His strikeout rate rose to its second highest mark, in turn.

Freddy Peralta has slowly become less reliant on his fastball, but in his first start, his velocity was well down. As a reminder, I am comparing his velocity as a starter, and he only made one start in 2020 to compare to. Luckily, the down velocity in his first start was just a blip, as he was right back to normal, and even at the level of his relief days, over the rest of the season. Throwing that hard even as a starter allowed him to post a strikeout rate over 30% and enjoy a big breakout year as he crossed the 100 innings threshold for the first time.

Unfortunately, James Paxton missed the rest of the season to injury after his velocity partially bounced back from his down 2020.

After a big velocity spike in his first start, Casey Mize failed to maintain the surge over the rest of the season. He actually recorded a velocity around 95 MPH in his next two starts, but in his fourth start, it fell to around 94 MPH and he wasn’t above that range again the rest of the way. If he would have maintained that velocity bump, I would have expected a nice jump in strikeout rate. It’s hard to believe that such a highly regarded prospect has only managed a 19.3% strikeout rate during what amounts to one full season of innings. He hasn’t even been able to push his SwStk% into double digits.

While Trevor Rogers couldn’t quite hold his first start velocity all season, he did hold onto most of his gains and it led to a breakout season, though he needed some serious help from lady luck to accomplish that, as there’s little chance he repeats anything close to a 5% HR/FB rate again.

Brad Keller didn’t fully hold his first start gains, but he did do enough to rebound off a decline from 2020. Though his velocity wasn’t a career high, he did post the highest strikeout rate of his career, though it still remained well below the league average. The big change here though was that he finally lost his BABIP magic, as that shot up to .347, well above anything he has posted in the past. He also suddenly struggled keeping his fly balls in the yard. This is the risk when buying a pitcher who has handily outperformed his SIERA over a relatively small sample, thinking it’s a skill. Even riskier is when the pitcher comes with a low strikeout rate, so there’s no value floor.

After a velocity spike during his first start, Kyle Gibson’s velocity dropped right back to where it was in 2020. While with the Rangers, he rode the fortune train toward massive SIERA outperformance. Sadly, his luck disappeared when he joined the Phillies, despite actually posting a higher strikeout rate and lower walk rate. He does still have that fantastic slider, so I keep thinking there’s more here, but he’s had enough years to prove it and simply hasn’t.

Oh Andrew Heaney, I simply cannot give up on you. A first start velocity spike got me excited, but he gave up that up quickly and he landed right where he typically does. And as usual, he posted solid skills, but gopheritis torpedoed his ERA. I’m cautiously optimistic that a new beginning with the Dodgers is all he needs to become the mixed league asset I always thought he could.