There’s not a lot of “right” ways to build a starting rotation in baseball. Several successful starting pitching groups feature either free agent signings, trade acquisitions or stop-gap veterans.
But if there is a right way to build a starting rotation, the Seattle Mariners might have the best argument for it.
The Mariners boasted arguably the best group of starting pitchers in baseball last season. It was the only rotation to have four pitchers start 30 or more games and all five starters had a sub-3.70 ERA. Four of the five hurlers (Logan Gilbert, George Kirby, Bryce Miller, Bryan Woo) were drafted and developed by Seattle. The only one that wasn’t (Logan Gilbert) was acquired via trade in 2022 and almost immediately handed a long-term extension.
The only two starters in that group that haven’t made the All-Star Game are Woo and Miller, who just completed their second major league seasons in 2024.
Which is why FanGraphs’ latest projections come at a bit of a shock.
For the 21st consecutive year, the popular baseball site released its ZiPS (Zymborski Projection System). The overall projections have the Mariners finishing around what they’ve been for the last several seasons: 85-90 wins when taking into account potential injuries.
Part of the projections include a drop off for two starting pitchers. Miller, after having arguably the best season in the rotation in 2024, is expected to have a 2.8 fWAR, the second-lowest among the group. Woo is projected to have a 2.4 fWAR. Seattle’s No. 6 starter Emerson Hancock is estimated to have a 0.2 fWAR.
Even with the estimated drop-off, FanGraphs still has the Mariners with the second-best starting rotation in baseball behind the Philadelphia Phillies.
FanGraphs said the following about their projections in the article detailing the projections:
In the very preliminary run of projected 2025 WAR, ZiPS puts all five of Seattle’s likely starters in the top 60 in the majors. And there’s no excessive extrapolation required either; all five have shown they can pitch convincingly well in the majors. The problem comes with the “what if.” ZiPS projects a big drop-off in ERA+ from Bryce Miller to the likely sixth starter, Emerson Hancock — a full 22 points (107 to 85), in fact.
FanGraphs mentioned the possible danger if Seattle suffers injuries to the starting rotation. As mentioned before, four starters opened 30 or more games. That health is unlikely to repeat. Hancock made 12 starts in 2024 due to three separate injury list stints from Woo and Castillo. If the Mariners have to go deeper than Hancock as the No. 6 pitcher, then it will likely mean call-ups for top pitching prospects Logan Evans and Brandyn Garcia.
The bullpen meanwhile, was projected for a drop-off of its own. But mainly due to the players they have rather than players expected to take a step back.
FanGraphs predicts good seasons from closer and 2024 All-Star Andres Munoz and relievers Gregory Santos and Matt Brash. After that, there’s a separation that the author of the predictions article, Dan Szymborski, described as a “gulf.”
The bullpen will look significantly different than it did in 2024. Brash is expected to be back by April or May, according to General Manager Justin Hollander. Santos will presumably be healthy after having an injury-ravaged 2024, JT Chargois was designated for assignment on Tuesday, Yimi Garcia is a free agent and four other relievers are up for arbitration.
Projection models aren’t the be-all, end-all. And FanGraphs worked its projections off the 2024 roster, leaving a lot of room for improvement.
But if the ZiPS model is correct, fans could be in for another dramatic and frustrating season in 2025.
