Food for Pfaadt: A Closer Look at Brandon Pfaadt’s High-Leverage Heroics

No team gets to the World Series without leaning on some of their depth, and part of what gets a team to the finish line is how this supporting cast performs. Name a championship squad, and it’s a safe bet it got some significant contributions from a handful or third and fourth starters, long relievers, hitters further down the lineup, etc.

I’m not a betting man, but I wouldn’t have picked Brandon Pfaadt to be one of those players for one of this year’s World Series teams. Pfaadt, who just turned 25 last week, had a bit of a rocky rookie season, posting a 5.72 ERA, 5.18 FIP, and 4.46 xFIP in 96 innings over 18 starts split by a pair of demotions to Triple-A Reno. He got hit for hard contact, and the strikeout numbers that mitigated the damage in the minors faded when he got to the majors in May. He did get stronger as the year went on, posting a 4.14 ERA, 3.89 FIP, and 3.89 xFIP in August and September — more on that later — but I wouldn’t have expected him to be on the mound for some of the biggest starts of the season — and for the Diamondbacks to win all of them.

The Diamondbacks were forced to use Zac Gallen and Merrill Kelly on the final weekend of the season, leaving Pfaadt to face Corbin Burnes on the road in Game 1 of the Wild Card Series. When he came back around, Arizona had a chance to clinch at home against the Dodgers in Game 3 of the NLDS. In the Championship Series, he started as close to a must-win Game 3 as you can get, down 0–2 to the Phillies, and then Game 7 on the road in Philadelphia. Three of those four starts were, at the time, the biggest game of the Diamondbacks’ season, and it was Pfaadt who had the ball.

The Championship Leverage Index measures how much impact a particular plate appearance or game has on a team’s chances of winning the World Series. Pfaadt’s postseason outings have featured an average cLI of 35.6; the only starter this postseason with a higher average cLI is Ranger Suárez, Pfaadt’s two-time opponent in the NLCS. No other starter has come particularly close.

It hasn’t been pretty the whole time. While his two starts at Chase Field have been outstanding — four hits and no walks over 10 scoreless innings — he recorded just eight outs and allowed three runs in that first start in Milwaukee, and his Game 7 start was a bit of a tightrope walk, though he managed to allow just a pair of runs. The Diamondbacks bullpen, anchored by Ryan Thompson, Kevin Ginkel, and Paul Sewald, deserves a ton of the credit in getting them this far. But in a postseason in which offenses have had the upper hand for the first four innings, and pitchers for the final five, Pfaadt has been strong enough in a handful of huge spots to keep Arizona alive.

There’s only so much we can learn from the first 16.2 innings of Pfaadt’s postseason career, but a few things stick out. He’s been particularly good at locating his pitches around the edges of the strike zone and letting the pitch movement take them there. He’s kept the four-seamer up in the zone, letting the changeup and sinker run to the arm-side and the sweeper and the rare curve come off the plate to his glove-side, turning pitches that look middle-middle into shadow strikes on both sides and pitches that look like shadow strikes into swings off the plate. He’s throwing more pitches outside the zone, but generating more swings — a good recipe for some swing-and-miss. Here’s a look at the 70 pitches the Phillies swung at this past series, 33 (or 47%) of which were whiffs:

His starts in Game 3 and Game 7 of the NLCS featured the two highest swing-and-miss totals of his young career despite the fact that he threw just 70 and 64 pitches, respectively.

This is Diamondbacks pitching coach Brent Strom’s vision, and Pfaadt’s work, in motion. Per MLB.com’s Steve Gilbert in July, before Pfaadt was recalled again late that month, he and Strom worked with outside pitching consultant and “purveyor of effective velocity” Perry Husband. The trio arrived at the suggestion that Pfaadt reposition himself from the third-base side of the pitching rubber to the first-base side, essentially shifting his release point about a foot in the horizontal direction of the plate. On the left-hand side below are the release points for the bulk of Pfaadt’s pitches in May and June; to the right, his pitches from July through the end of the regular season:

The idea was that the pitches would appear more often to be strikes out of Pfaadt’s hand, making them more difficult to lay off. He could then use his repertoire, which features pitches moving in both directions, to move them away from the center of the plate as they traveled. In other words, the tunnels might be more effective if they weren’t coming in at such a dramatic angle to begin with. Sure enough, he started to get more swings at bad pitches, higher strikeout rates, and weaker contact.

During the postseason, he’s been inching further and further to his left; his last three starts had the center-most average release points of his season:

And he’s seeing those trends continue:

Another reason for the shift, according to Gilbert, was that Husband suggested that Pfaadt bringing his release point closer to in line with home plate would impact his effective velocity, which is Husband’s own concept. It’s worth noting that, while Statcast’s perceived velocity metric shows a nearly identical gap between his actual and perceived velocity before and after the change, this metric accounts only for how far in front of the plate he is releasing the ball (his extension) and not how far to one side or another. The change of a foot in horizontal release point can mean the ball has up to four to six fewer inches of hypotenuse to travel before reaching home plate, even for a pitcher with above-average extension like Pfaadt. Husband has written far more on effective velocity than I ever will, but this is a point worth considering as we continue to measure how release point impacts a hitter’s available time to react.

Pfaadt’s non-fastball offerings — those that are moving the most — are working particularly well this postseason. He’s throwing the changeup, which had been a serious problem before his option, a hair faster than he was in the regular season at 87.2 mph, and locating it beautifully; a full 53.3% of them have ended up in the shadow zone. That pitch has yielded a .301 wOBA thus far despite a .198 xwOBA. In his final prospect report before Pfaadt graduated, our Eric Longenhagen wrote that the changeup was “the pitch he has the least consistent feel for locating,” and while such a small sample isn’t proof positive that he’s found it, we are getting a glimpse of how dangerous the arsenal can be when that pitch is finding the outside corner to lefties. Over time, he’s also gotten a little more comfortable adding the pitch to his mix against righties:

The sweeper, going the other direction, has righties flailing, earning whiffs on 52.8% of swings and allowing just a .211 wOBA and a .149 xwOBA. He’s gotten into some trouble with both the four-seamer and the sinker, which he’s started to use more in the last few months particularly to move away from lefties, but he also uses the fastballs disproportionately when behind in counts, so that may have something to do with the success hitters have had.

Pfaadt has been able to deploy this pitch mix effectively enough against hitters on both sides this postseason, and that’s been the difference between a ticket home and a ticket to Arlington. Arizona has one last best-of-seven series ahead with the Rangers, and Pfaadt is lined up to start Game 3, another monumental spot for a 25-year-old rookie. But the Diamondbacks wouldn’t be here if it weren’t for him, and if they’re going to finish the job, it’s going to take more high-leverage heroics from the young starter.