Who is the Ace of the Padres Pitching Staff in 2026?
The once formidable San Diego Padres rotation has been absolutely ravaged by injuries and player departures entering 2026. In a season where San Diego seems to have more questions than answers, no on-field question marks are bigger than the starting pitching staff. The man once considered the ace of the staff, Yu Darvish, is almost certainly shut down for the season. Beyond Darvish, Dylan Cease hit the road in free agency, signing a massive deal with the Toronto Blue Jays. So now who will headline a rotation starving for some consistency?
New Guys
The Padres geared up for 2026 by seeking out value in low-risk, high-reward signings. Some of those were new rotational arms. The two most likely candidates for arms in the back half of the rotation are German Marquez and Walker Buehler. Marquez is coming off a brutal stretch of seasons with the lowly Colorado Rockies. In 2025, he pitched to an ERA of 6.70 in his 126.1 innings. Coors Field, of course, plays a role in these numbers, and Marquez is a former all-star, earning a nod in 2021. Despite his previous success and escape from Coors Field, it’s easy to rule Marquez out of ace talks.
Buehler is a more interesting case. The former Los Angeles Dodger has been decimated by injuries throughout his career, receiving two UCL repairs in the 2020s. His most recent return has not been pretty. In his final season with the Dodgers in 2024, he was worth -1.1 WAR in the regular season, yet a heroic playoff performance resulted in the Red Sox signing him to a big one-year contract. It did not work out. Buehler had a 5.45 ERA in 112.1 innings with the Red Sox. His baseball reference reveals there may be some improvement in 2026 with the Padres, courtesy of his 82nd percentile average exit velocity in 2025, but we can still remove Buehler from ace conversations.
San Diego Legend
Joe Musgrove is one of the most beloved players on the Padres roster every year. It’s hard to believe the San Diego local hasn't pitched since 2024. When on the field, Musgrove is exceptional. In his two non-injury-affected seasons for the Padres in 2021 and 2022, he pitched to a 3.18 and 2.93 ERA, respectively. Even in his shortened seasons in 2023 and 2024, he was great, particularly in the 2024 playoffs, where he sustained his UCL injury. Musgrove is by far a top-three pitcher in the Padres rotation, second when healthy. However, considering his delayed return from injury, he misses out on the staff ace title.
Continued Success for Pivetta?
In 2025, the rotation was led by a stellar Nick Pivetta season. In his first season with the Padres, he put up a 2.87 ERA, finishing sixth in Cy Young award voting. The Padres, thankfully, retained Pivetta courtesy of his four-year deal. Despite success in 2025, the stellar season is an outlier in his career numbers. Before 2025, Pivetta had never pitched to an ERA below four in his career, let alone below three. With the Boston Red Sox, his previous team, his best ERA was 4.04 in 2023. It’s easy to be excited about Nick Pivetta, but he is due for some regression, and it may not be pretty. Despite being in Baseball Reference's 99th percentile in pitching run value in 2025, his underlying metrics reveal the amount of luck involved. Pivetta allowed an average exit velocity of 90.3 MPH, placing him in the 22nd percentile. Beyond that, he allowed a hard-hit percentage in the 15th percentile, not ideal for projecting a low ERA. Pivetta will be an acceptable rotational arm in 2025, but do not expect him to repeat his under-three ERA 2025 season.
True Ace
It seems that an injury-shortened 2025 has led people to forget how good Michael King is. The Padres re-signed King to a three-year deal in the offseason, by far their best move entering 2026. In 2025, King made just 15 starts, yet he still pitched to a 3.44 ERA while dealing with nagging injuries. 2024 was King’s best self. He earned Cy Young votes courtesy of a 2.95 ERA in his first season as a full-time starter. King earns most of his value from the strikeout, putting up 10.4 strikeouts per nine batters in 2024. Punchouts come easy when you have some of the best off-speed pitches in the game. King had an off-speed run value in the 96th percentile in 2024. The 31-year-old is by far the biggest acquisition of the Juan Soto trade, and when healthy, is far and away the best pitcher in the Padres rotation. Expect a sub-3.50 ERA with great strikeout numbers for King this season.
