Toronto Blue Jays vs Seattle Mariners Picks, Predictions, Props & Odds for ALCS Game 4

• Luis Castillo and the Mariners look for the first home victory of the series when they host Max Scherzer and the Blue Jays tonight
• Scherzer last two regular-season starts were an unmitigated disaster but he has a solid history against the Mariner hitters
• See my Blue Jays vs Mariners expert picks for Game 4, plus player props to target and the updated TOR/SEA odds

Despite dropping Game 3 in lopsided fashion last night (13-4), the Seattle Mariners () remain in control of their best-of-seven ALCS with the Toronto Blue Jays (). If they can muster the first home victory of the series tonight in Game 4, they will be within one win of their first-ever World Series appearance.

On paper, the pitching matchup favors the Mariners. Seattle turns to Luis Castillo (3.54 ERA, 1.18 WHIP in reg. season), who was near-perfect in his first start of the postseason (no runs on one hit and four walks over 4.2 IP against the Tigers). Toronto counters with veteran Max Scherzer (5.19 ERA, 1.29 WHIP in reg. season), who ended the regular season by allowing 11 earned runs on 17 hits over just 5.2 innings in his final two starts. He hasn’t pitched since.

First pitch of Game 4 is scheduled for 5:33 pm PT from T-Mobile Park in Seattle. Below, I will set out my expert Blue Jays/Mariners picks and predictions, my favorite player prop to bet, and the latest SEA/TOR Game 4 odds.

Go to: Expert Picks || Player Props || Current Game 4 Odds

Seattle Mariners vs Toronto Blue Jays Game 4 Expert Picks

• Blue Jays moneyline (+105) at Caesars
• Over 7.5 runs (-105) at FanDuel
• Scherzer over 3.5 Ks (-155) at BetMGM

It’s not hard to see why Seattle is favored in Game 4 (listed at -120 or shorter). They have the more reliable arm on the mound and they have been outstanding after a loss (12-4 in the last 16). Castillo has yet to allow a run this postseason, and his high-velocity fastball and wipeout slider have the potential to dominate any lineup.

But he’s had some trouble with control, and several Blue Jays have a strong track record against him. Seattle is also just 1-4 in their last five as a home favorite. Baseball is so often a game of streaks, and the Blue Jay bats busted out in a huge way last night. I expect more fireworks from their lineup, which is dangerous from top to bottom.

The most compelling angle is on the total. The over has been a cash cow in Toronto/Seattle games, hitting in seven of the last eight meetings between these clubs, including each of the last two. I don’t have a lot of trust in either starter tonight due to a constellation of concerning stats.

TOR vs SEA Game 4 Player Props

MLB player props as of October 16, 2025 from FanDuel & DraftKings.

The pitcher props are telling. Max Scherzer’s strikeout total is set at a remarkably low 3.5, though with heavy -158 juice on the over. This suggests the market expects him to be on a very short leash, likely not pitching deep into the game. His outs line is just 11.5 (less than four innings). For bettors confident in Scherzer’s ability to turn back the clock, the over on his strikeouts is the better option. Even when he’s been getting tagged this season, he’s still been missing plenty of bats.

Luis Castillo’s strikeout line is set at 4.5, with plus-money on the over. While the Blue Jays lineup has a solid history against him, Castillo’s electric stuff gives him a high ceiling for strikeouts in any start. The over on 1.5 earned runs allowed is heavily favored at -154, indicating oddsmakers expect the potent Blue Jays offense to scratch across a couple of runs even against Seattle’s ace.

Toronto Blue Jays Career Statistics vs Luis Castillo

The Blue Jays’ lineup has had a reasonable amount of success against Luis Castillo, posting a collective .256 average and .739 OPS. Catcher Alejandro Kirk has been particularly effective, hitting .500 with a home run in eight at-bats and a 1.375 OPS. Four other Jays have a homer off of Castillo: Nathan Lukes, Isiah Kiner-Falefa, Anthony Santander, and Andres Gimenez.

Daulton Varsho has been completely neutralized, going 1-for-12 with four strikeouts and one walk.

Seattle Mariners Batters vs Max Scherzer

The Mariners only have a .204 average in 54 total ABs against Scherzer, but four of their 11 hits left the yard. Eugenio Suarez has two of those homers in 19 ABs, but is batting just .158 against the future Hall-of-Famer. Victor Robles is an ugly 0-for-7 with a pair of Ks. JP Crawford has the best overall history, going 3-for-7 with a double and a walk (1.071 OPS).

Seattle Mariners vs Toronto Blue Jays Odds for Game 4

The Mariners remain slight home favorites (-120 at FanDuel and slightly shorter at other books) but the line has been narrowing over the last 12 hours. The best price on the Toronto moneyline is now just +105 at bet365. vig-free probability of Seattle winning at approximately 53.7%, while Toronto holds a 46.3% chance. Despite the Blue Jays’ offensive onslaught in Game 3 and the Mariners’ ten-run output the game prio, the run total is sitting at just 7.5 with roughly even odds both ways.

Game 4 Odds Movement

The betting market has seen significant movement since lines opened. The Mariners opened as -142 favorites, but that line has been bet down to -120, a 22-cent shift toward the Toronto Blue Jays.

Conversely, the total has seen sharp movement in the opposite direction. After opening at 7.5 with the over favored at -122, the over price has grown despite the MLB public betting percentages showing that 84% of bets are on the over. This is a strong indicator of professional money backing a lower-scoring affair.

Game 4 Public Betting Splits

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