Seattle Mariners 2025 preview
A lot of fan bases are disappointed in their favorite team’s offseason, but I would suggest that no fan base is more annoyed than the one rooting for the Seattle Mariners. This is a playoff-worthy starting rotation without the offense it deserves. With a group that finished 29th in batting average, 15th in on-base percentage, and 22nd in OPS, many expected to see Seattle get a little bit aggressive in the pursuit of some free agent hitters or maybe orchestrate a trade to send a starter out and bring a hitter in.
Well, that didn’t happen, as the Mariners are basically going into the season with nearly all of the same offensive pieces that they had last season. The offense did add Randy Arozarena in July, so he’ll be there for a full season this time around, and Donovan Solano in January. But, that’s it. This was arguably the best starting staff in baseball last season and the Mariners will go into 2025 hoping that the offense finds a way to be better.
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Seattle is not a small-market city, but the Mariners are treated like a small-market team by ownership. This is an organization that hasn’t been in the top 10 in Opening Day payroll since 2008 and has been below the league median every year since 2019. Coincidentally, the Mariners have one playoff appearance since 2001 and haven’t won a division title since that year, in which the Mariners went 116-46 and tied the all-time record for wins in a season.
The last two teams have finished better than their record, with the 88-74 Mariners in 2023 more like a 91-71 team by Pythagorean Win-Loss. Had that record come to fruition, the M’s would have made the playoffs over the Rangers, who eventually won the World Series. The 2024 Mariners were 85-77, but 89-73 by Pythag W-L. That record, again, would have gotten them into the playoffs.
So, for GM Jerry Dipoto and the rest of the front office, those are positive signs for a team that has won 90, 90, 88, and 85 games the past four seasons. For a fan base that doesn’t care about hypotheticals, it isn’t good enough.
2025 Seattle Mariners Odds
(odds from DraftKings as of Feb. 24)
World Series: +2800
AL Pennant: +1100
AL West: +250
Win Total: 84.5 (-110/-110)
Make Playoffs: Yes -110 / No -110
Seattle Mariners Preview: Offense
After shedding a lot of the biggest culprits in the K% department from 2023, the Mariners…led the AL in K%. They were only percentage points behind the Rockies, who have to deal with the atmospheric and scientific impacts of the Coors Field Effect. Seattle hitters struck out nearly 27% of the time a year removed from striking out 25.9% of the time. Mike Ford (32.3%), Jarred Kelenic (31.7%), Teoscar Hernandez (31.1%), and Eugenio Suarez (30.8%) were all removed from the equation and the Mariners struck out even more.
Seattle was fourth in BB%, trailing only the Yankees among AL teams, so they were able to get back some of their lost plate appearances by drawing walks, but all the strikeouts, walks, and deep counts led to a .224 batting average that was only better than the White Sox. And Chicago lost 121 games. At least the Mariners were significantly better than the White Sox in all the other offensive categories.
There are so many things I can look at with the Mariners. The high K% is inexcusable and has to change. New hitting coach Kevin Seitzer was a pretty good MLB hitter and was most recently with the Atlanta Braves, who have had some hitting success. The Mariners also began hitting better late in the season when Scott Servais was fired and Dan Wilson was hired, along with the appointment of Edgar Martinez as temporary hitting coach. Martinez is now the Senior Director of Hitting Strategy.
The Mariners were third in wOBA and second in wRC+ in September with a K% of 23.1%. They didn’t really sacrifice their walk rate or their contact authority. They simply put more balls in play. That is a great sign going into this season and maybe a reason why Dipoto didn’t go on a spending spree, instead opting to hope for the in-house personnel to continue on that trend line.
What concerns me is that the Braves were at the forefront of the launch angle craze and hitting the ball in the air at a high rate in T-Mobile Park doesn’t really yield the same return it does in other venues. The Mariners batted just .214/.307/.358 at T-Mobile Park. Because all of the hitters know about what the conditions do to offensive numbers, they were excessively patient, leading to a 10.2% BB%, but also a 28.4% K% from having so many two-strike counts. Seattle was 12th in wOBA on the road, batting .234/.315/.392. Still not good enough, but better.
One of the biggest benefactors of the Wilson/Martinez tutelage was Julio Rodriguez, who has to be a superstar for the M’s to get where they want to go. Over the final month of the season, he batted .328 and hit seven homers in 126 PA. Arozarena did not have the same spike, but he did post a 122 wRC+ in 239 PA after the trade from the Rays, due in large part to his high walk rate and a BABIP spike. Those are the two most important bats in this lineup by far. Several others need to be better, but these guys need to carry the load.
Seattle Mariners Preview: Pitching
Led by their starting staff, the Mariners had a top-10 set of arms. Seattle was second in ERA and third in FIP, but the starting pitchers really did do the bulk of the heavy lifting. The rotation accounted for 15.2 fWAR of the team’s 16.9 fWAR. Starters posted a 3.38 ERA with a 3.64 FIP. Collectively, the rotation only issued a 4.9% BB% to lead the league by far and they also ranked sixth in K%.
Despite those numbers, Seattle starters only went 59-50 as the pitchers of record, another nod to the offense and how problematic it was. When the Mariners scored at least three runs at home last season, they were 43-7. That also means the Mariners scored fewer than three runs in 31 of their 81 home games. So, the starters did everything that they could, including the most innings pitched as a starting staff with 942.2, which was 31.2 more than any other rotation.
I always get scared with rotations that did what Seattle’s did last season, though. Why? Because four starters made 30+ starts. In total, the Mariners only used seven starting pitchers and six of them had at least 12 starts. The only main guy to miss time was Bryan Woo and he made 22 starts over 121.1 innings. Having four starters throw at least 175 innings is so incredibly rare, let alone in this day and age of specialization and starters really only being conditioned to go five innings.
Being blessed like that on the health front doesn’t happen often and, as I’ve already discussed, a drop-off from the pitching staff is going to hurt even more unless the offense can get things going in the right direction. Logan Gilbert, George Kirby, Bryce Miller, and Luis Castillo all had ERAs of 3.64 or lower and FIPs of 3.91 or lower. There were 29 starters total that qualified for the ERA title and had a 3.64 or lower and Seattle had four of them. That is extreme dominance, to say the least.
I don’t have much more to add here. The Mariners have Emerson Hancock, but that’s really about it in terms of proven depth, so they’ll have to stay healthy. For the sake of the season, those five guys above will have to stay healthy. Jackson Kowar could be an option in the summer after recovering from Tommy John surgery, but he has a 9.12 ERA and a 5.99 FIP in 74 MLB innings and hasn’t started at the MLB level since 2021.
Seattle will have to thread the needle here. To this point, Gilbert, Castillo, and Kirby have been workhorses. Miller took the big leap in innings and production last season. Woo might be next. But, these five guys are collectively the most important starting pitchers in baseball, unless the offense can create some margin for error.
The Mariners bullpen was ninth in ERA and 15th in FIP, as a high walk rate cut into a high strikeout rate. They’re basically running it back with the same group sans Austin Voth, who signed in Japan, and Ryne Stanek, who finished last season with the Mets anyway.
Seattle Mariners Player to Watch
OF Victor Robles
The most pleasant surprise of the 2024 season for the Mariners was Robles. The Nationals got tired of waiting on him to blossom in June and released him. Seattle picked him up, and he proceeded to bat .328/.393/.467 with a .375 wOBA and a 154 wRC+. Prior to that, the only seasons in which Robles was an above-average hitter were 2018 (66 PA) and 2023 (126 PA). For his career, he’s only a .247/.321/.370 hitter with a 90 wRC+. He was a top-10 prospect by Baseball Prospectus in 2017, 2018, and 2019, but never panned out…
Until he joined the Mariners. Obviously, everybody in the baseball community is very skeptical of the breakout. He ran a .370 BABIP, which is possible with his speed, as he stole 34 bases in 91 games. But, his contact quality is really poor. His sub-30% Hard Hit% and sub-7% Barrel% are well below league average. His average exit velocity of 86.7 mph was also poor. He did play well in the field, but I don’t really see any reasons to buy into the offensive uptick.
The one caveat to that is that Robles slashed .389/.465/.528 in the final month of the season. His .459 BABIP was remarkably unsustainable, but that was a big chunk of time after Wilson and Martinez took over on the coaching staff. He did up his average exit velo to 89 mph and his Hard Hit% to 30.9% in that time. I still think it was an outlier, and I think the Mariners will find out the hard way.
Seattle Mariners Season Win Total Odds & Prediction
I really want to believe in the Mariners. I have before. I’ve mostly been right in taking the pulse of this team. The pitching staff is exceptional. The offense is underwhelming. Lather, rinse, repeat. And the Mariners leave their rotation zero wiggle room for injury or any other hiccup.
The returns from the last month and a half of the 2024 season are encouraging, though. I like the Seitzer hire, and I like that Martinez is around more. Seattle went 21-13 on Wilson’s watch, and the vibes around the team seemed better as more wins came. From the time Wilson took over (Aug. 23) until the end of the season, the only offenses with a higher wOBA were the Dodgers, Diamondbacks, Cubs, and Phillies. The Mariners were 18th in K% and second in BB%. Something clicked.
Can it click and stay throughout the season? Can the pitching staff hold up? This is the type of team I usually want to bet on for a win total because I think the range of outcomes is pretty wide. Given the same health, I think this team does better than 84.5 wins. Hardly a guarantee. Which is why I’d rather gamble on some markets. Mariners to be the No. 3 seed is +750. That’s better than +250 to win the division. They’re +800 to be the No. 2 seed. If you think the ceiling for this team is 90-something wins, the AL Central champ may not get that. I think those are two worthwhile ways to explore betting the Mariners with a lower-risk, higher-reward play.
Lean: Over 84.5; Picks: Mariners No. 3 Seed (+750); No. 2 Seed (+800)
