With all seven of the pitchers that made multiple starts for them last season returning for 2026 and under club control for multiple years, the Mariners aren't expected to be doing much within the free-agent starting pitching market other than being interested spectators.
The title of best starting rotation in baseball definitely took a bit of a hit in 2025 with George Kirby, Logan Gilbert and Bryce Miller all missing significant time due to injury. When they returned from their stints on the injured list, the trio never really found the consistency that was shown in 2024.
But Bryan Woo took a major step forward in his development, making a career-high 30 starts and posting a 15-7 record with a 2.94 ERA. In 186 2/3 innings pitched, he struck out 198 batters with only 36 walks. He earned a spot on the American League All-Star team and likely will finish in the top 10 in American League Cy Young voting.
Meanwhile, Luis Castillo showed he can still be a viable member of the rotation as he moves into his mid 30s. He made all 32 of his scheduled starts in 2025, posting an 11-8 record with a 3.54 ERA. In 180 2/3 innings pitched, he struck out 162 batters with 46 walks. That stability was needed with multiple members of the rotation on the injured list at varying points.
The projected starting rotation of Gilbert, Woo, Castillo, Kirby and Miller is one that most teams would envy.
Last offseason, the Mariners listened to trade offers on all of their starting pitchers, but weren't really inclined to move them with the exception of Castillo.
Why? As part of his contract extension, Castillo was guaranteed $24 million a season through 2027 with a $25 million vesting option in 2028. Trading Castillo would create payroll flexibility to upgrade the roster in other areas. But he also had a no-trade clause, which was limiting on potential deals. That no-trade clause has expired so the Mariners could trade him this offseason if desired. It's not something they are looking to do, but the right deal might entice them. It's why the free-agent starting pitching market is a factor. If a team like the Mets or Giants can't upgrade their rotation with free agents, then a trade for Castillo might seem like a path to improvement.
If the Mariners do move Castillo or another starter, there are plenty of viable starters in this free-agent class to serve as a No. 4 or No. 5 starter on a one or two-year contract.
Seattle has also proven to be good at developing starting pitchers. The Mariners have Logan Evans and Emerson Hancock as viable depth along with prospect Jurrangelo Cijntje, Ryan Sloan and Kade Anderson in the farm system.
Here's a look at the top free-agent starting pitchers:
The top tier
Dylan Cease (30) -- He can be a maddening pitcher and it's not because of his mustache that screams, "look at me I'm a firefighter or Patreon poet." For as talented as he is with his ability to miss bats and generate weak contact, his overall results seem like they should be better. Part of it is the walks (3.8 per nine innings) and the overall pitch inefficiency. He's still durable, making at least 32 starts in each of the past five seasons.
Ranger Suárez (30) -- Since being converted to a full-time starting pitcher, Suárez has been outstanding. From 2022 to 2025, he posted a 38-29 record with a 3.59 ERA. While he doesn't log some of the innings and starts like some of the other free agents, his innings -- an average of 147 over the past four seasons -- have been quality.
Framber Valdez (32) -- Putting Valdez in the top tier is based on talent and production. His combination of sinker/slider from the left side can be absolutely devastating to hitters. When he's right, the production provided is dominant. He's also durable. He's made at least 28 starts in each of the last four seasons, including 31 starts in three of them, pitching 767 2/3 innings. Only San Francisco's Logan Webb (820) has logged more innings. The question marks surround Valdez's attitude. Even before the incident where he purposely crossed up his catcher, resulting in a fastball off César Salazar's chest, there were plenty of in-game meltdowns that led to blowup innings and wasted starts.
All three pitchers have qualifying offers attached to them, meaning any team that signs him will be assessed a penalty, including loss of draft pick(s) based on their payroll.
The best of the rest (age)Shota Imanaga (32) -- qualifying offer
Tatsuya Imai (28)
Michael King (31) -- qualifying offer
Lucas Giolito (30)
Zac Gallen (30) -- qualifying offer
Zach Eflin (32)
Merrill Kelly (37)
Brandon Woodruff (32)
There are some very good pitchers in this group led by King and Gallen. Imai hasn't officially been posted by the Saitama Seibu Lions. If he is posted, he will generate heavy interest due to his age and lack of a qualifying offer. A team will have to pay a posting fee of more than $22 million and then likely pay more than $20 million a season for him.
The restTyler Anderson (36)
Chris Bassitt (37)
Paul Blackburn (32)
Walker Buehler (31)
Griffin Canning (30)
Carlos Carrasco (39)
Aaron Civale (31)
Alex Cobb (38)
Patrick Corbin (36)
Nestor Cortes (31)
Nabil Crismatt (31)
Anthony DeSclafani (36)
Jon Duplantier (31)
Erick Fedde (33)
Chris Flexen (31)
Austin Gomber (32)
Jon Gray (34)
Foster Griffin (30)
Kyle Hart (33)
Andrew Heaney (35)
Kyle Hendricks (36)
Adrian Houser (33)
Andre Jackson (30)
Jakob Junis (33)
Anthony Kay (31)
Zack Littell (30)
Michael Lorenzen (34)
Kenta Maeda (38)
Tyler Mahle (31)
German Marquez (31)
Nick Martinez (35)
Steven Matz (35)
Dustin May (28)
Triston McKenzie (28)
John Means (33)
Miles Mikolas (37)
Wade Miley (39)
Frankie Montas (33)
Jordan Montgomery (33)
Chris Paddack (30)
Martín Pérez (35)
Cody Ponce (32)
Cal Quantrill (31)
José Quintana (37)
Max Scherzer (41)
Michael Soroka (28)
Marcus Stroman (35)
Tomoyuki Sugano (36)
Kona Takahashi (29)
José Ureña (34)
José Urquidy (31)
Justin Verlander (43)
Jake Woodford (29)