The Sub-1.00 ERA Club: Why Are They Dominating?

Honorable Mention: Chris Bassitt, Toronto Blue Jays

When examining the 2025 Toronto Blue Jays, their pitching staff was likely the last area baseball fans expected to see someone succeed in. However, Chris Bassitt has pitched like one of the top arms in the sport so far this year.

Through five starts, Bassitt has recorded 28.2 innings pitched, in which he’s posted an ERA of 1.88 He’s also managed to strike out an impressive 28.6% of batters he’s faced, recording a 1.3 fWAR along the way.

A big part of Bassitt’s success has been his high strikeout rate, which is currently the 14th-best mark among qualified starters. When striking out this many batters, it’s hard to fathom his results being anything besides elite.

Additionally, Bassitt finds success by keeping hitters guessing, as they have virtually no idea what to expect when they’re in the batter’s box.

Bassitt throws seven different pitches in his vast arsenal, including a sinker, cutter, curveball, splitter, sweeper, four-seamer, and slider. He’s used his sinker significantly more than the other pitches, and it’s found immense success.

Despite clocking in at just 91.4 mph, his sinker has been challenging. Hitters are currently hitting .211 while slugging just .237 against it as well. With a pitch this efficient as your primary pitch, it’s easy to see why he’s found this level of success.

Although his cutter may not possess the movement profile needed to be considered an elite pitch, it has certainly performed just like an elite cutter would.

His cutter is his second most used pitch, and opponents are currently hitting and slugging just .150 against it. It also has a terrific whiff rate of 30.2%, which has helped it tremendously.

Bassitt does get a boost from his funky delivery, which makes his stuff a lot harder to pick up. At release, his arms work together to form a 40-degree angle, which isn’t normal for your average starting pitcher. His glove also moves a lot, which is known to cause deception for hitters at the plate.

Bassitt’s success in 2025 is more unique since he hasn’t had any major differences in what he’s doing this year. His stuff is relatively the same, and his approach appears similar to previous seasons.

The only difference in his arsenal this year is that his splitter usage is slightly higher, and the pitch has been very good in the process. He’s executing his splitter better than he has in past seasons, adding to his success.

Bassitt has had a slightly more horizontal release point, which has allowed his sweeper and splitter to have more horizontal movement as a result. This pitch mix makes for a very high ground-ball rate, which is key for the success of a starting pitcher.

Out of all four pitchers mentioned on this list, it may be the most difficult for Bassitt to sustain this success since he hasn’t made any huge adjustments. However, what he’s done early this season has been phenomenal, and it’s been exactly what the Blue Jays needed.

Yoshinobu Yamamoto, Los Angeles Dodgers

When the Los Angeles Dodgers inked Yoshinobu Yamamoto to a 12-year, $325 million contract back in December of 2023, they expected him to become one of the best pitchers in Major League Baseball. Now, in 2025, this hope has officially become a reality.

Yamamoto has started five games to this point, in which he’s recorded a 0.93 ERA across 29 innings pitched. In addition to this, Yamamoto has recorded a fantastic strikeout rate of 35.2% while also racking up 1.0 fWAR.

Although Yamamoto battled injuries for much of the 2024 season, we saw glimpses of the ace-caliber pitcher Yamamoto was in NPB. In 2025, this version of Yamamoto has fully broken out.

Part of this success appears to be due to Yamamoto needing some time to gain comfort with the MLB baseball itself. The NPB baseball is smaller, more tacky, and comes with smaller laces, making it a lot different for pitchers to adjust to when entering either league.

Due to this newfound confidence with the MLB baseball, Yamamoto has gained over an inch of vertical break on his fastball in 2025, which makes the pitch far more deceptive and harder to hit than it previously was. Not only this, but an extra inch of vertical break allows for better tunneling with his splitter.

Not only does his splitter have more deception now that his fastball has more vertical break, but it’s seen improvements on its own. He’s gained just over an extra tick on the pitch, and he’s also ramped up the usage of it as well. He’s even limited the splitter’s vertical break, which adds to its movement profile.

As a result, the splitter has arguably been his best pitch in 2025. Opponents are currently hitting just .077 against it to go with a .153 xwOBA, a whiff rate over 50%, and low exit velocities.

Similar to Bassitt, Yamamoto doesn’t just succeed off of two pitches either, as his mix is very deep. He throws a curveball, cutter, sinker, slider, and sweeper in addition to his four-seamer and splitter, making hitters constantly guess what may be coming their way.

Because of this, Yamamoto is made to pitch deeper into games. During a hitter’s second and third trips to the plate, they might not have seen his entire arsenal, giving Yamamoto the upper hand in how he chooses to attack hitters.

He’s also excelled at keeping the ball on the ground and has limited extra-base hits, and that has carried him to success. His ground-ball rate sits at 63.5% so far in 2025, meaning if Yamamoto isn’t striking hitters out, a lot of the contact he’s allowing is on the ground.

For all of these reasons, Yamamoto has become a truly complete pitcher as well as someone the league will fear for the entirety of the 2025 season and beyond.

Kodai Senga, New York Mets

Although the New York Mets may not have had the same financial commitment to Kodai Senga as the Dodgers had to Yamamoto, they certainly had similar expectations for Senga when they signed him to a five-year, $75 million deal back in 2022.

Senga has struggled to stay healthy since coming over to MLB, but when he’s been on the field and healthy, he’s been dominant. Now that he’s healthy again in 2025, we’re seeing a similarly dominant version of Senga.

So far in 2025, Senga has pitched to a 0.79 ERA across 22.2 innings in four starts, a mighty impressive beginning to the season. Also, Senga has already racked up 0.5 fWAR and struck out 23% of batters he’s faced. His 486 ERA+ currently leads the league as well.

Senga’s success is very interesting given the fact that his fastball has struggled so far in 2025. For any pitcher, it’s difficult to find success without a good fastball, but that’s especially true for someone who relies on the tunneling of his forkball off the pitch.

Opponents have hit .310 against his four-seamer while simultaneously slugging .552 against the pitch. This is far different from his 2023 season where opponents hit just .244 and slugged just .399 against his four-seamer.

Outside of the four-seamer and forkball, Senga’s cutter appears to be the main pitch he uses to confuse hitters and catch them off guard. This pitch adds just enough deception to get him by. Senga has thrown it just over 20% of the time, which is a significant amount considering his forkball usage has been a little higher.

When looking for someone who’s mastered a pitch, it’s hard to think of anyone besides Senga and his forkball. He’s currently using the pitch nearly 27% of the time, which is seemingly the most he can use the pitch without it becoming overbearing or too predictable.

He’s done a great job commanding the pitch, as he’s kept it in the bottom part of the strike zone all season, which is the optimal location for a forkball.

Considering that the on-field results have been so good for Senga so far in 2025, if he stays healthy, there’s no doubt in my mind that he can continue to pitch like one of the sport’s best pitchers.

Tyler Mahle, Texas Rangers

The Texas Rangers have been one of baseball’s scariest teams early in the 2025 season, and a large reason for this has been the club’s starting pitching. With Jack Leiter, Kumar Rocker, Jacob deGrom, and now MLB’s ERA leader, Tyler Mahle, all finding success, it’s easy to see why they’ve been so scary.

Through five starts, Mahle has recorded 26.2 innings pitched, in which he’s miraculously posted an ERA of 0.68. He’s also struck out 24.8% of batters he’s faced, recording a 0.8 fWAR along the way.

A big part of Mahle’s success in 2025 has been finally staying healthy, as he’s really struggled to stay on the field in recent seasons. He barely stayed off the injured list in 2024 and underwent Tommy John surgery the year prior.

Just like every other pitcher in the sub-1.00 ERA club, a big part of Mahle’s success has been because of his splitter. His splitter has nearly seven fewer inches of vertical break, which is a big deal for the pitch’s movement profile.

Because of this, his splitter has registered amazing results. Opponents are hitting just .156 against it while slugging just .188 as well. Its average exit velocity has been very good also at just 85.4 mph.

His fastball and splitter have tunneled very well, following another trend seen in this club. Unlike his splitter, his four-seamer has a high vertical break, which allows for such a good tunnel to be sustainable and successful.

With this vert-heavy fastball, Mahle has been able to pound the top of the zone and use this to add deception to his splitter. He’s thrown the splitter for a strike 73% of the time, mostly at the lower part of the zone, showing this difficult tunnel take shape.

Again, Mahle shares something else in common with the other three pitchers here, as his cutter is just good enough to throw hitters off and make them think about another pitch besides just the four-seamer and splitter.

He’s also limited extra-base hits at an elite rate, as he has yet to allow a homer while only allowing three extra-base hits to this point.

Mahle is throwing better than he ever has in his career, and if he continues to use his stuff to the best of his ability, this may be more sustainable than you may think.