Dylan Cease and his AL-leading strikeout stuff headline the series opener in Seattle, and I’m riding the Toronto Blue Jays ace.
The Blue Jays open a weekend series in Seattle riding high after a nine-run Canada Day romp, and they hand the ball to Dylan Cease against the Seattle Mariners and Luis Castillo.
Cease has been overpowering lately, and a Mariners lineup that hasn’t seen much of him sets up my favorite play of the night.
Read on for my Blue Jays vs. Mariners predictions and MLB picks for this Friday, July 3 matchup.
Blue Jays vs Mariners predictions
Blue Jays vs Mariners best bet: Dylan Cease Over 8.5 strikeouts (+120)
Dylan Cease is a push away from what feels like one of the best pitching seasons in Toronto Blue Jays history. The right-hander has some of the nastiest stuff in baseball, a triple-digit fastball, a wipeout breaking ball, and an AL-leading 128 strikeouts in 83.1 innings.
That 13.8 K/9 usually carries him over his strikeout number, and he’s punched out eight or more in seven of his last eight starts. The one thing that trips him up is command, like last time out against the Texas Rangers, when he walked five.
I’m confident the ace settles back in against a Seattle Mariners lineup that ranks 20th in the majors at 8.64 strikeouts per game and hasn’t seen much of him.
Julio Rodriguez has just two career at-bats against Cease, and Josh Naylor owns a modest .640 OPS in 25 at-bats.
I’d play this until even money, so make sure you’re getting it at +100 or longer.
COVERS INTEL: That strikeout surge is powered by a deadly slider (+11 run value, per Baseball Savant), against which opposing hitters own just a .159 average and .215 slugging.
Blue Jays vs Mariners same-game parlay (SGP)
The Blue Jays have won seven of their last 10 against the Mariners, including an epic seven-game ALCS last fall to reach the World Series, and they’re rolling off that Canada Day blowout.
I like Over 7 total runs, too, backing Toronto to break through against Luis Castillo.
And Cease Over 8.5 strikeouts anchors it, especially with the extra off day helping him work deeper and rein in his command.
Blue Jays vs Mariners SGP
- Over 7
- Blue Jays moneyline
- Dylan Cease Over 8.5 strikeouts
Blue Jays vs Mariners home run pick: Sean Keys (+790)
Bet on Sean Keys and turn the ignition. The Blue Jays rookie announced his arrival with a massive three-run homer on Canada Day, giving the fan base a well-deserved jolt of energy.
We don’t have much of a sample through 12 MLB at-bats, but the 23-year-old went deep 21 times in 67 minor-league games before his call-up, so the pop is very real.
Keys draws a nice matchup against Mariners starter Castillo. His first big-league homer came on a hard, outside fastball from Freddy Peralta, and Castillo is another fastball-heavy arm.
Play this one north of +700, and keep it to a quarter unit.
- Best bets: 2-1, +0.79 units
- SGPs: 1-2, +0.69 units
- HR picks: 0-3, -0.75 units
Blue Jays vs Mariners odds
- Moneyline: Blue Jays -130 | Mariners +110
- Run line: Blue Jays -1.5 (+135) | Mariners +1.5 (-155)
- Over/Under: Over 7 (-115) | Under 7 (-105)
Blue Jays vs Mariners trend
The Toronto Blue Jays have won seven of their last eight games at T-Mobile Park, a friendly backdrop for another road win in Seattle. Find more MLB betting trends for Blue Jays vs. Mariners.
How to watch Blue Jays vs Mariners and game info
| Location | T-Mobile Park, Seattle, WA |
| Date | Friday, 7-3-2026 |
| First pitch | 10:10 p.m. ET |
| TV | KING 5, SN |
| Blue Jays starting pitcher | Dylan Cease (4-4, 3.02 ERA) |
| Mariners starting pitcher | Luis Castillo (3-6, 4.93 ERA) |
Blue Jays vs Mariners latest injuries
Blue Jays vs Mariners weather
Odds are correct at the time of publishing and are subject to change.
Not intended for use in MA.
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