Introduction

More MLB picks: Seattle Mariners · Houston Astros

Seattle Mariners’ surge is undeniable with a 4-1 mark in their last five games at 5.8 runs per outing, signaling a lineup in rhythm and a team worth backing in this MLB prediction. Houston has been steady but less explosive at 4.2 runs across their recent five, and the head-to-head edge favors Seattle with five wins in the last eight meetings. With both sides consistently generating offense, this matchup projects value on the Mariners and a strong lean to the Over.

Game Time

Slated for Sunday, September 21 at 07:10 PM ET at Minute Maid Park, the short left-field porch changes the math.

Odds & Spread Line

• Seattle Mariners: -143
• Houston Astros: +119

Total: 8

• Run Line — Seattle Mariners: -1.5 (+115)
• Run Line — Houston Astros: +1.5 (-137)

Latest Team Records

Seattle Mariners: 85-69 (Win %: 0.552)
Houston Astros: 84-70 (Win %: 0.545)

Injury Report

Seattle Mariners are missing Ryan Bliss (Knee), listed as 60-Day-IL; Gregory Santos (Knee), listed as 60-Day-IL; Jackson Kowar (Shoulder), listed as 15-Day-IL. No other significant injuries are reported.

The Houston Astros are currently healthy with no major injury concerns.

Key Player Stats

Seattle Mariners

• Cal Raleigh: 0.246 AVG, 56 HR, 118 RBI
• Eugenio Suarez: 0.228 AVG, 47 HR, 112 RBI
• Julio Rodriguez: 0.269 AVG, 31 HR, 94 RBI

Houston Astros

• Jose Altuve: 0.261 AVG, 26 HR, 74 RBI
• Jeremy Pena: 0.303 AVG, 16 HR, 58 RBI
• Christian Walker: 0.233 AVG, 23 HR, 82 RBI

Team Analysis

Seattle Mariners

The Mariners are riding a 4-1 surge in their last five games, fueled by consistent scoring at 5.8 runs per contest. That offensive pace has been anchored by Cal Raleigh’s deep power threat and Julio Rodriguez’s ability to drive in runs, providing a balanced attack. Even with a sub-.500 road record, their current rhythm and confidence tilt this matchup in their favor.

Over the last 10 games, Seattle has gone 9-1 while maintaining the same 5.8 runs per game output, an elite stretch of consistency. Eugenio Suarez has added critical production in the middle of the order, ensuring this lineup doesn’t rely on a single bat. With this form translating directly into head-to-head success against Houston, the Mariners’ offense is positioned to dictate the tempo.

• Batting Average: 0.244
• Total Runs Scored: 728
• Home Runs: 227
• OBP: 0.32
• SLG: 0.42
• OPS: 0.74
• ERA: 3.89
• WHIP: 1.23

Away Record: 38-42 • Home Record: 48-27
Last 5 Games: 4-1 (5.8 RPG)
Last 10 Games: 9-1 (5.8 RPG)

Houston Astros

The Astros’ recent 3-2 record across their last five games shows steadiness but lacks the dominant surge their opponent is riding. Jose Altuve continues to bring timely power, yet overall run production has stayed at 4.2 per game, below Seattle Mariners’ current pace. At home, Houston has been solid with 46 wins, but they have not consistently generated the same offensive momentum as the Mariners.

Stretching to their last 10, Houston Astros’ 6-4 mark with 4.4 runs per game reflects a capable but less explosive profile. Jeremy Pena’s contact hitting has kept rallies alive, though Christian Walker’s run production has not been enough to tilt results against top-tier competition. With Seattle Mariners’ balanced offense finding rhythm, Houston Astros’ home edge is diminished in this matchup.

• Batting Average: 0.251
• Total Runs Scored: 652
• Home Runs: 169
• OBP: 0.317
• SLG: 0.398
• OPS: 0.715
• ERA: 3.83
• WHIP: 1.22

Away Record: 38-37 • Home Record: 46-34
Last 5 Games: 3-2 (4.2 RPG)
Last 10 Games: 6-4 (4.4 RPG)

Head-to-Head History

Seattle Mariners lead 5–3 (Last 8 games)

• September 20, 2025: SEA 6 @ HOU 4
• September 19, 2025: SEA 4 @ HOU 0
• July 20, 2025: HOU 11 @ SEA 3
• July 19, 2025: HOU 6 @ SEA 7
• July 18, 2025: HOU 1 @ SEA 6
• May 25, 2025: SEA 3 @ HOU 5
• May 24, 2025: SEA 1 @ HOU 2
• May 23, 2025: SEA 5 @ HOU 3

Over/Under Trends

Seattle Mariners’ last 10 games have averaged 8.8 total runs, with 5 games that would have cleared today’s total of 8.

Houston Astros’ last 10 games have averaged 8.5 combined runs, with 5 games clearing the same number of 8.

Moneyline Betting Prediction

Seattle Mariners’ 9-1 stretch in their last 10 games, combined with a 5-3 head-to-head edge over Houston, makes them the clear side to trust. With Cal Raleigh’s power, Julio Rodriguez’s run production, and recent offensive consistency outpacing Houston Astros’, the Mariners’ form and matchup profile point decisively to the stronger team.

The Seattle Mariners are the sharp side on form and splits.

Over/Under Prediction

Last five form shows the Houston Astros at 4.2 RPG and the Seattle Mariners at 5.8, giving context for the number.

These teams are combining for 10.0 runs per game recently — above the posted total of 8.0. That points toward the Over 8.0.

Bookmakers

You’ll find these markets at: FanDuel, MyBookie.ag, Caesars, BetOnline.ag, LowVig.ag, BetUS, BetMGM, Fanatics.

Parlamaz may earn affiliate commissions from links in this article.

John TamburinoVerified

Lead Analyst — data-first, former college baseball.

John Tamburino grew up on travel baseball and three years of varsity basketball, then played college baseball before shifting to analytics. He still watches everything—from weekday tennis to all major league sports—and will never forget the Diamondbacks’ World Series run. At Parlamaz, John blends trusted data feeds with matchup context to find real value—no fluff, no paywalls.

X (Twitter)