With Just Days Until The 2025 MLB Trade Deadline, Who Could The Mariners Make A Move For?
By Jeffrey Nooney, edited by Charles Hamaker
Seattle, WA - Welcome to trade deadline week, a favorite week for many MLB fans across the entire season. This is the week you find out exactly what your favorite teams’ front office thinks of their ball cub so far and what they may need. Do they believe in who they have? Do they think this is a lost season? In the case of the Washington Nationals, did your front office get fired already? A lot of questions will be answered in the coming days, and for Mariners fans, they hope to see the final push to make the playoffs for just the second time in the last 24 seasons.
President of baseball operations Jerry Dipoto and general manager Justin Hollander, plus the rest of the Mariners front office, have shown to be one of the most aggressive teams at the deadline in recent memory, both in acquiring high end talent and sending high end talent away in years past. They have already traded for first baseman Josh Naylor this season, while adding players like Randy Arozarena and Luis Castillo over the last few years. When it comes to shipping off talent, the Mariners have also sent away players like relievers Paul Sewald and Kendall Graveman, who were key members of the bullpen at the time of being traded, in the middle of trying to still contend for a playoff spot.
As previously mentioned, Seattle already filled a massive hole in their lineup with the addition of Josh Naylor. Naylor is going to be a key member of the Mariners down the stretch, but he should not be the only addition this front office makes to this team. Many still believe that Seattle should fill needs at third base and in the bullpen. In addition to the corner infield spot and bullpen help, many believe that it’s in the best interest of the Mariners to acquire another starting pitcher considering the struggles from young starters Logan Evans and Emerson Hancock while it’s unsure what will come from Bryce Miller for the remainder of 2025. Who are players at those positions who could be available? We take a look here.
Arizona Diamondbacks third baseman Eugenio Suárez during the teams April 27th, 2024 game against the Seattle Mariners at T-Mobile Park. (Photos by Liv Lyons for Circling Seattle Sports)
Third Base
This may not be the biggest of needs for the Mariners, but I still believe that they need an upgrade for at least this year at the position. Ben Williamson is a wizard defensively, but he leaves a lot to be desired at the plate in his current form. Williamson is slashing .252/.289/.307/.596 with an OPS+ of just 75, 25% below league average. While he does strike out at around a league average rate, he does not walk as much as you’d like. His walk percentage sits at 4.5%, exactly 4% below league average. With his already low slugging percentage, he needs to get on base at a league average, at least, especially at a premium position like third base.
There are not a lot of third base options available that would be significant upgrades at the deadline. Old friend Eugenio Suárez is the best option at third base, and is trending to be the best bat available at the deadline. Suárez has been one of the best power hitters in all of baseball this season, and is currently slashing .248/.321/.577/.898 with an OPS+ of 143, which is a career-high for the former Mariner. He has hit 36 home runs so far, and leads the National League with 87 RBIs. Suárez will be a free agent after this season, but the Diamondbacks reportedly are commanding a high price tag for his services despite having seemingly no interest in re-signing him once the season comes to a close if they were to hold on to him. Should the Mariners make a deal for him, expect to part ways with two or more top tier prospects for two months of Suárez.
Nolan Arenado is another name that has been talked about in trade rumors dating back to the last offseason. Arenado’s name carries a lot of weight, but he is no longer the same player who was leading the league in home runs or batting average. This season, he is slashing just .235/.295/.368/.664 with an OPS+ of just 86, 14% below league average. He has ten home runs, 43 RBI and 15 doubles, and strikes out at a remarkable 9.3% of his plate appearances. His best trait is still his defense, as he has received the Gold Glove award ten times in his career. He is signed through 2027, and is owed 16 million in 2026 and 15 million in 2027. That alone may turn the Mariners off of him, but he is still a solid player and an offensive upgrade over Ben Williamson. While he could be viewed as such, you’d have to see the money he’s owed and the decline of his overall play with his age and imagine that Seattle’s front office wants no parts in that.
Outside of those two older options, Minnesota Twins super-utility player Willi Castro is a name that’s also been floated alongside the Mariners and he’d certainly be an interesting fit for Seattle especially considering that the Twins have relief arms that Dipoto and Hollander would love to acquire. While he’s a fun name given the versatility, and everyone knows how this front office loves their utility players that can play a multitude of positions, Castro has played just 13 games at third base this season and hasn’t particularly played there a ton in his career overall. His advanced numbers this season leave a lot to be desired, both in the field and at the plate, so you have to wonder if the Mariners would just be better off with Williamson. The Mariners have been looking into Castro, per MLB.Com’s Daniel Kramer, but so have other contenders.
Relievers
The Mariners bullpen has been a bit up and down this year, and they need some higher leverage arms to lean on besides the two that take up most of the spotlight. Matt Brash has come back and has been lights out, but he is fresh off of his Tommy John surgery, and may not be able to be the work horse we have come to expect from him down the stretch. Andrés Muñoz has also been great, but after those two, things have been a bit shaky. Right now Seattle is using Gabe Speier, Eduard Bazardo, Carlos Vargas, Casey Legumina, Trent Thornton and Jackson Kowar behind Brash and Munoz. Besides Speier, the rest of the bullpen leaves a lot to be desired in high leverage situations. There are quite a few closers available at the deadline, and the Mariners need to be aggressive to add another arm or two and Dipoto has said already that the organization plans to be as aggressive as anyway when it comes to adding in that area.
The best reliever that could have been traded, Emmanuel Clase of the Cleveland Guardians, is no longer going to be traded. He was placed on paid leave through August 31st, pending a MLB investigation into gambling. Removing Clase from the list, the next best reliever that could be traded is Ryan Helsley from the St. Louis Cardinals. Helsley led the National League in saves in 2024, and already has 21 this season. He has pitched to a 3.00 ERA and a 1.38 WHIP. His WHIP this year is a bit high, but he is still a dominant arm that averages 99 MPH with his fastball. Helsley is a free agent after this season, but the Cardinals still expect to get a big haul in return.
Mason Miller from the Athletics is a fun idea, but there’s a very low likelihood that the currently Sacramento based organization would send their star relief arm to a divisional rival. The Pirates are likely to trade two of their relievers, closer David Bednar and lefty Dennis Santana, before Thursday’s deadline. Bednar has had a nice bounce back since being sent down last season, and is not a free agent until after the 2026 season. Santana has bounced around the league a bit, but has really turned himself into a high leverage type pitcher in Pittsburgh over the last season and a half. This year, Santana has an ERA of just 1.39 over his 45.1 innings of work. The Mariners could sure use another lefty out of the bullpen with Speier being their lone lefty arm in the bullpen over the last few years outside of Tayler Saucedo before he was sent back down to AAA Tacoma earlier this season.
The Twins seem destined to sell off just about all of their bullpen arms. The four arms I think the Mariners should look at are Jhoan Duran, Griffin Jax, Danny Coulombe and old friend Justin Topa. Duran, the Twins closer, has been a dominant arm for the Twins over the past three and a half seasons. He has a career 2.47 ERA, and has saved 74 games over his career. His price tag will be heavy, as he is not a free agent until 2028. Griffin Jax has turned himself into a strikeout machine this season with his 14.1 strikeouts per nine innings, and like Duran, is not a free agent until 2028. The problem with Duran and Jax is that Minnesota is seemingly asking a very steep price for either of them, with reports coming out in recent days that the Twins want two top 100 prospects (Seattle has eight, if you’re unaware) in return for just one of those two arms. Danny Coulombe is a 35 year old veteran left handed pitcher that is having a career season, posting a 1.16 ERA through his 31 innings of work and is a free agent after this season. He’s an older option but might be more in the price range for the Mariners compared to the previous two. Topa has battled injuries since being traded to the Twins in the Jorge Polanco deal, but has had a really good season this year. He had one really bad game that saw him give up five earned runs in just a third of an inning, but otherwise he has been solid.
A team that’s seemingly never traded their talent, despite being largely mediocre and below that for the last decade or so, is the Colorado Rockies. Sources indicate that the Mariners have been doing their homework on a few Colorado arms, including Jake Bird, Seth Halvorsen and Juan Mejia. They might not be the flashy names previously mentioned, but they certainly could help Seattle out more than their current internal options as the Mariners search for a return to the postseason.
Starting pitching
Given the struggles of some of the in house options at starting pitcher for Seattle, with Emerson Hancock getting a strong share of starts earlier in the season as George Kirby worked back from an injury in Spring Training and Logan Evans spending some more time in the rotation recently as Hancock struggled in a few notable starts, it’s not a crazy thought to imagine that the Mariners may look for a starter. There’s a large question mark looming around right-handed starter Bryce Miller, who has been largely ineffective this year for Seattle due to a few reasons, most recently two stints on the injured list with elbow inflammation and a bone spur behind the elbow on his throwing arm. It just doesn’t seem like “Big Tex” is going to be able to help the Mariners down the stretch and currently their two younger starters aren’t helping them as they hunt a playoff berth, so what’s available to them on the starting pitcher market? There are quite a few options floating out there according to rumors, including Sandy Alcantara (Marlins), Tyler Anderson (Angels), Shane Bieber (Guardians), Edward Cabrera (Marlins), Dylan Cease (Padres), Zach Eflin (Orioles), Zac Gallen (D-backs), Andrew Heaney (Pirates), Adrian Houser (White Sox), Mitch Keller (Pirates), Merrill Kelly (D-backs), Charlie Morton (Orioles), Joe Ryan (Twins), Luis Severino (Athletics), Michael Soroka (Nationals), Tomoyuki Sugano (Orioles). Some of those names are more high ends than perhaps Seattle would want to make an offer for, considering the names they have coming down the pipeline in the starter department (Ryan Sloan and Kade Anderson are certainly very exciting to think about), and a starter isn’t necessarily the highest priority ahead of Thursday so you have to wonder if the Mariners even worry about it.
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Check out our previous Seattle Mariners articles here.
Check out our previous articles with writing by Jeffrey Nooney here. Check out his previous work with Sodo Mojo by clicking here.
Cover photo of this article by Liv Lyons, check out her portfolio here.
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