4-seamer, faster and better?

In April, I was reading an article on a website. In the article, the reporter indicated that a team’s relievers are throwing hard this season and the fastball velocity of those relievers significantly increases this year. After reading the article, I was wondering which team’s bullpen throws really hard in the 2023 season.

To understand a little bit more, I went to check on the statcast website.

Average Pitch Velocity (Four-seam fastball, Relievers, ~2023.05.23)
Team	Velocity (mph)
Orioles	95.7
White Sox	95.7
Royals	95.7
Phillies	95.5
Nationals	95.5
Cardinals	95.4
Twins	95.0
Pirates	94.9
Red Sox	94.8

Firstly, it’s very important to take a look at the Baltimore Orioles. The Orioles already won 31 games. By far, their record is the second best in the majors. A possible reason why the Orioles have the second best record is that their bullpen has done a great job. The Orioles bullpen now post a 3.00 ERA and their WHIP is 1.23. This season, the Orioles relief pitchers throw four-seamers hard with an average velocity of 95.7 mph. In particular, Felix Bautista has 11 saves thus far. He owns a 1.50 ERA and a 1.25 WHIP over 24 innings. Bautista uses his four-seamer more than 60% of the time this year and the average velocity of his four-seamer is 98.7 mph. At the same time, the average velocity of Cionel Perez’s four-seamer is over 96 mph. And, Mike Baumann throws his four-seamer more than 50% of the time and the average velocity is over 96 mph as well.

In addition, the White Sox relief pitchers are throwing hard this year. The average velocity of their four-seamers is over 95 mph. In the White Sox bullpen, Reynaldo Lopez has collected 4 saves and his four-seamer velocity is 98.7 mph, on average. However, Lopez’s ERA is over 6 and the White Sox relievers now own an ERA over 5. But, Garrett Crochet is back to the mound after the Tommy John recovery. He made 3 relief appearances so far and his four-seamer velocity is 96.6 mph, on average. It will be interesting to see his performance after missing the entire 2022 season. In the meantime, the Royals relievers throw four-seam fastballs hard. The average velocity of their four-seamers is nearly 96 mph. Aroldis Chapman signed a 1-year deal with the Royals before the spring training. His four-seam fastballs frequently touch triple digits this season and the average velocity of his four-seamer is 99.5 mph. Moreover, Carlos Hernandez is another hard-throwing pitcher in the Royals bullpen, the average pitch velocity of his four-seamer is 98.9 mph. Nonetheless, throwing hard might not always generate good results. The Royals bullpen now have an ERA of 4.60, which ranks 26th among 30 MLB teams. Finally, as we can see, there must be hard-throwing pitchers from the Phillies’ bullpen, the Nationals’ bullpen, the Cardinals’ bullpen and the Twins’ bullpen, because the average velocity of four-seam fastballs is over 95 mph from each bullpen. Nevertheless, among these 4 teams, only the Cardinals and the Twins post a bullpen ERA below 4. Looking at these teams with the average pitch velocity of relief pitchers’ four-seam fastballs over 95 mph, the Orioles bullpen certainly has performed well with an ERA of 3.00, which ranks second among 30 MLB teams. Furthermore, the Cardinals relievers and the Twins each have an ERA below 4 at this moment. Nonetheless, the White Sox bullpen owns an ERA over 5 and the Royals relievers’ ERA is 4.60. Baseball is not easy. Throwing hard doesn’t necessarily guarantee good results. Throwing hard might be useful, but there must be other factors besides the pitch velocity.