Last season, the Seattle Mariners and the Boston Red Sox didn’t get to meet in the postseason because of the way the bracket shook out; the fifth-seeded Red Sox played the fourth-seeded New York Yankees for the right to play the top-seeded Toronto Blue Jays, with the second-seeded Mariners sitting on the other side of the bracket from the AL East gauntlet.
If Seattle makes the playoffs this season, it’ll likely look similar; Boston and New York seem locked into the fifth and fourth seeds, while the Mariners will either enter as the third-seeded AL West winner or the sixth-seeded Wild Card, awaiting on the other side of the bracket.
But it’s getting late early for Seattle; the Red Sox took the opener of the teams’ three-game series in Boston last night, and the Mariners have no more margin for error if they want to make the postseason. Tonight’s middle game, which is set to begin at 6:45 p.m. ET, is a must-win affair for the visitors.
Bryan Woo will start for Seattle, and the Red Sox will counter with Jedixson Paez.
Let’s break down this plausible (but now highly unlikely) ALCS preview with some odds and lines at DraftKings Sportsbook.
Seattle Mariners at Boston Red Sox Best Bets
- Boston Red Sox Moneyline (-123): Given that Boston has played like a 114-win team over the last two months, -123 is pretty friendly odds, especially since Woo has not looked like the same pitcher he was last season, when he finished fifth in Cy Young Award voting.
- Over 7 (-122): Similarly, it’s just not worth backing a low-scoring game when one pitcher has a near-6 ERA on the road and the other is an untested rookie with six earned runs in three career innings. Each of the Red Sox’s last three games have gone over.
Seattle Mariners at Boston Red Sox prediction, preview
For months, AL West has been right there for the taking, and at 48-49, the Mariners were right in the thick of it at the All-Star break, with FanGraphs giving Seattle roughly a 50-50 chance at ultimately claiming the division. In fact, the Mariners were favored at FanGraphs every day until July 24. However, Seattle went just 11-16 in August, posting the league’s third-worst OPS across the month, and with a six-game deficit in the division and a 5.5-game deficit in the Wild Card race, any rally might well be too little, too late. Even Cal Raleigh’s late-season bounce-back — he’s posted a .324/.425/.971 slash line with seven homers in his last 10 games — hasn’t been enough to lead to wins. In part, that’s because the Mariners’ pitching has been a disaster; their starters have posted a 5.05 ERA since the Midsummer Classic, and their relievers (6.38) have been even worse. A few outliers, including a 22-0 disaster against the Milwaukee Brewers, make the raw numbers look worse than they’ve been on a game-to-game basis, but Seattle’s staff certainly hasn’t been good. Top prospect Kade Anderson has helped stabilize it with two solid starts, but closer Andrés Muñoz needs to get back on track after blowing a save last night.
Boston, by contrast, has had a lot more stability over the last couple of months, as a franchise record-tying 15-game winning streak in July vaulted the Red Sox into the playoff picture and they haven’t looked back. In July and August, Boston combined for a 38-16 record, and while catching the Tampa Bay Rays atop the AL East feels unrealistic, the Red Sox still have a shot at securing home-field advantage in the Wild Card series with the Yankees, who they trail by three games. In August, Boston had baseball’s second-best OPS, even though new acquisition Adley Rutschmann has struggled at the plate, and Roman Anthony’s long-awaited return from injury should help sustain that form even when Jahmai Jones (1.363 OPS in 22 games since joining the team) inevitably cools off. Furthermore, the Red Sox have sported both a top-10 rotation and a top-10 bullpen for the season as a whole, with Sonny Gray turning back the clock to serve as the staff ace and Aroldis Chapman maintaining form as one of baseball’s most untouchable relievers at the age of 38. Additionally, Brayan Bello, who was horrendous as a starter, has posted a 1.53 mark across 13 appearances (59.0 innings) as a long reliever.
Woo posted a sub-3 ERA in both 2024 and 2025, finishing fifth in Cy Young Award voting in 2025, but he hasn’t been the same so far this season. In 25 starts, he’s pitched to a 4.36 ERA, including a 5.27 mark since the start of June, and he allowed six earned runs in just four innings in his most recent outing. Still, advanced numbers suggest that he’s gotten somewhat unlucky, as he sports a 67th-percentile expected ERA and 87th-percentile pitching run value. Like he did last season, he’s peppered the zone, ranking in the 95th percentile in walk rate, and that should help limit a Boston team that has earned free passes at a below-average rate. Woo ranks in just the 10th percentile in hard-hit rate and the 21st percentile in average exit velocity, but that might not hurt him too much against the Red Sox, who have thrived on soft contact. However, his location splits are an issue; he’s posted a near-6 ERA away from pitcher’s paradise T-Mobile Park this season, and Boston’s offense has been somewhat more impactful at home.
Thankfully for the Mariners, Páez is a completely untested starter. He’s pitched just three innings in MLB, giving up six earned runs across three separate outings with the Chicago White Sox, but since returning to the rotation with Triple-A Worcester, he’s been solid, recording a 2.92 ERA across three starts. Additionally, the Venezuelan made a few solid starts in Double-A, and he had a 2.79 mark across seven starts for High-A Greenville in 2025. He’s enjoyed a relatively high strikeout rate in the minors, fanning 10.9 batters per nine innings in Double-A and Triple-A this season, and that could play well against the whiff-prone Seattle offense. However, Páez has also been slightly more homer-prone than average this season, and despite their overall offensive struggles, the Mariners still have a few mashers, especially with Raleigh seeing the ball well. Páez was significantly better at home across all levels (although he’s never pitched at Fenway Park), and Seattle has had baseball’s fifth-worst road offense. I don’t expect a star-level performance from Páez, but four innings and two earned runs seems like a reasonable expectation.
Seattle Mariners at Boston Red Sox pick, best bet
Best Bet: Boston Red Sox Moneyline (-123)
Even with a potentially shaky Páez on the mound for his starting debut, I trust the Red Sox’s bullpen to step up once the starters leave the game, and Woo’s road form is quite poor.
Strong Lean: Over 7 (-122)
Páez likely won’t escape entirely without damage, and 15 of Woo’s 25 starts have included at least seven runs. Even for the Mariners, seven total runs is a low bar.
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