2025 MLB Odds: Seattle Mariners vs. Toronto Blue Jays ALCS series preview and prediction

For the first time in nearly a decade, the Toronto Blue Jays are back on the ALCS stage. Waiting for them is a Seattle Mariners team fresh off one of the most dramatic wins in playoff history: a 15-inning epic that finally pushed them through to their first ALCS since 2001.

These two teams entered Major League Baseball together in 1977, but they’ve never crossed paths this deep into October, until now. Expect fireworks, drama, and a series that could go the distance.

Make sure to check out our complete list of MLB game odds, MLB futures and MLB specials and props.

Mariners vs. Blue Jays ALCS Odds and Betting Trends

Oddsmakers have installed Toronto as a slight favourite to win the series, priced at -130, with Seattle hovering close behind at +110.

Toronto owns home-field advantage for Games 1, 2, and (if needed) 6 and 7 at Rogers Centre, where they scored 431 runs during the regular season, the third-most in MLB. They also went 4–2 against Seattle this year, including a three-game sweep at T-Mobile Park back in May.

But the Mariners have been the hotter team down the stretch. Both teams ranked among the top five in one-run games this season, meaning this ALCS could feature tight finishes and late-inning swings that could turn bettors’ tickets upside down.

Seattle Mariners

Seattle’s Game 5 win over the Tigers demanded the use of three starting pitchers (George Kirby, Luis Castillo, and Logan Gilbert) and almost every reliever. Jorge Polanco’s walk-off single sent the city into euphoria, but at the end of the day, they trained the pitching staff.

Pretty much only Bryce Miller avoided the mound, which all but confirms he’ll start Game 1 in Toronto. The key question is whether right-hander Bryan Woo, Seattle’s ERA leader in 2025 and one of MLB’s most consistent “quality start” arms, will be available. Woo missed the ALDS with a pectoral strain but is reportedly close to returning. 

Offensively, the Mariners are deeper than they’ve been in years. Cal Raleigh, the favourite for AL MVP, and Julio Rodríguez headline a lineup that thrives in big moments. Toronto’s pitchers lean heavily on the splitter, but Raleigh (1.159 OPS vs. splitters) and Rodríguez (1.091 OPS) feast on them. Add in Randy Arozarena, who’s capable of going bananas for stretches, Josh Naylor’s bat-to-ball and high IQ, Eugenio Suarez’s slug and J.P. Crawford’s clutch gene, and the Mariners have the pop and patience to punish late-inning mistakes.

Toronto Blue Jays

Toronto enters the ALCS having dispatched the Yankees 3–1 in the ALDS behind lights-out hitting and dominant starts from Kevin Gausman and rookie phenom Trey Yesavage. Gausman will take the ball in Game 1 on a week’s rest, followed by Yesavage in Game 2. Yesavage struck out 11 and held New York hitless through 5.1 innings in his playoff debut. 

Toronto’s offence, led by Vladimir Guerrero Jr., has been relentless. Guerrero torched the Yankees, hitting over .500 with three homers and nine RBIs in four games. Even without Bo Bichette, who remains sidelined with a lingering injury but could return mid-series, the Jays’ contact-heavy approach gives them constant scoring pressure. Toronto struck out less often than any team in baseball this year and finished in the top three in both batting average (.265) and on-base percentage (.333).

If there’s a weak link, it’s the bullpen. Toronto relievers have posted a 6.30 ERA this postseason. Against a team like Seattle, that vulnerability looms large.

MLB ALCS Prediction: Who Will Win Mariners vs. Blue Jays?

This series feels destined for six or seven games. The Blue Jays’ pitching alignment gives them a clear edge in Game 1, and their lineup will be tough to contain early. But Seattle’s grit, bullpen depth, and late-game magic make them a dangerous underdog once the series stretches out.

Seattle stuns Toronto in a winner-take-all Game 7 at Rogers Centre to reach its first-ever World Series.

Best Bet: Mariners to Win the ALCS in 7 Games (+100)