The Minnesota Twins’ pitching staff evolved into one of the MLB’s best last season. Individually, Sonny Gray and Pablo López garnered Cy Young attention. But they dominated as a team, especially with their four-seamers.
Four-seamers come in a variety of shapes. The ones with the flattest trajectories and the fastest velocities perform the best. That doesn’t mean pitchers without those qualities can’t succeed, but the game gets easier for the pitchers who are the flattest and have the most velocity.
It’s meaningful, then, that Minnesota’s rotation collectively had one of the flattest four-seamers in the league:
*Data used to create this graph and all following graphs is courtesy of Alex Chamberlain’s Pitch Leaderboard Tableau Page
Trailing only the Texas Rangers, Minnesota threw four-seamers that were, on average, 0.27 degrees flatter than the rest of the league by Vertical Approach Angle Above Average (VAA AA). It may not sound significant, but it means that Twins pitchers can throw effective four-seamers in much more of the zone:
*Image is Chamberlain’s
The graph above shows where flat four-seamers perform better and how much better they perform in those spots. The two thick black lines depict the top and bottom of the strike zone. Blue areas represent the lowest swinging-strike rates (SwStr), while darker shades of orange represent the highest.
With Minnesota’s average being just between 0.2 and 0.4 on the graph, you can see how much more vertical space they had to work with. Throwing low four-seamers to induce whiffs is still not a great idea, but there’s room for error.
The Twins achieved this feat as a unit. Joe Ryan’s five-foot release point makes his four-seamer appear to rise. Although Bailey Ober (6’9”) is significantly taller than Ryan (6’2”), Ryan achieved a flat four-seamer in much the same way – by releasing the ball low from the ground.
López reworked his four-seamer with Driveline’s help before the season and followed suit. His 5.5-foot release point and increased velocity (up to 94.9 mph) created a dominant four-seamer.
Some pitchers, like Kenta Maeda and Gray, didn’t have remarkably flat four-seamers. Still, they were flat enough not to alter the team’s average much.
Naturally, the Twins forced a lot of swinging strikes:
Twins starters have the second-highest SwStr in the league (14.2%). For reference, Ober’s 15.6% was in the 93rd percentile among starters last season. Colin Rea’s 14.2% mark was in the 90th percentile.
By improving their four-seamers, the Twins prevented runs at a high rate. Minnesota’s starters had the third-best ERA in the league, which had much to do with their four-seamer dominance.
We can further see their dominance through weighted on-base average (wOBA):
Statisticians calculate ERA, specifically expected ERA (xERA), using expected weighted on-base average (xwOBA). Pitchers who limit extra-base hits, or just hits and baserunners entirely, will achieve the best wOBAs.
Notably, the Twins had the fifth-best wOBA on four-seamers. Their ability to miss bats, avoid walks (second-best K-BB%), and limit extra-bases (ninth-best SLG) allowed them to be among the best four-seamers in the league.
Minnesota has a chance to be even better in 2024. López, Ryan, and Ober are returning, but Gray and Maeda have moved on to St. Louis and Detroit, respectively. Louie Varland and Chris Paddack should step into their place.
Varland’s stellar four-seamer is comparable to Ryan’s by VAA AA. Paddack’s is meaningfully steeper, but his impressive 95.5 mph could help him succeed with a low wOBA. Come April, every pitcher taking the Minnesota mound will have an exciting four-seamer.
