The American League West rivalry heats up at Daikin Park this Tuesday, May 12, 2026, as the Seattle Mariners (19-22) continue their critical four-game series against the Houston Astros (16-25). Both teams are navigating turbulent early-season waters; Seattle is looking to find offensive consistency to back their elite pitching, while the injury-riddled Astros are fighting to stay relevant in a division race that is quickly slipping away.

The Pitching Matchup

The Seattle Mariners will turn to right-hander Bryan Woo (2-2, 4.02 ERA). Woo has been a steady presence in a Seattle rotation that ranks among the league’s best in overall efficiency. Known for his high-velocity fastball and exceptional control, Woo has racked up 38 strikeouts over his early starts. His primary challenge on Tuesday will be navigating a Houston lineup that, despite the team’s struggles, still ranks second in the American League in wRC+. Woo has shown a tendency to work deep into games, which will be vital for a Mariners team looking to bridge the gap to their high-leverage relief arms.

The Houston Astros counter with right-hander Tatsuya Imai, who steps into the rotation as Houston continues to juggle a league-high 15 players on the injured list. With key starters like Hunter Brown and Cristian Javier sidelined, Imai faces a trial by fire against a Mariners lineup featuring dangerous power hitters like Cal Raleigh and Julio Rodríguez. While Imai brings an intriguing arsenal of off-speed pitches, he will be tested by a Seattle offense that leads the league in walk rate.

Best Bets and Analysis

Moneyline: Mariners (-136)

The Mariners enter as the favorite, and the statistical edge lies with the visitors. Seattle’s pitching staff maintains a significant advantage over a depleted Houston rotation and a relief corps that currently ranks near the bottom of the league in FIP. While the Astros’ offense remains dangerous—led by the perennial threat of Yordan Alvarez—the Mariners’ bullpen (led by closer Andrés Muñoz) is far more reliable in tight, late-game situations. At -136, the price reflects Seattle’s 52.9% win probability in this matchup.

Over/Under: Under 8.5 Runs (-105)

While Houston’s park is often associated with high scores, the Mariners’ pitching philosophy tends to suppress explosive innings. Bryan Woo is adept at inducing weak contact, and Seattle’s defense has been stellar in the early going. Conversely, the Mariners’ own offensive struggles—ranking in the bottom third of the league in runs per game—suggest this contest will be a low-scoring, tactical battle rather than a shootout.

Player Prop: Julio Rodríguez Over 1.5 Total Bases

Rodríguez has historically thrived in Houston, and he enters this game showing signs of a breakout after a slow April. Against a relatively inexperienced starter in Imai, expect the Mariners’ superstar to find gaps in the outfield. Whether through a multi-hit performance or an extra-base hit, Rodríguez is a strong candidate to lead the Seattle charge.

Final Verdict

This matchup is a story of two different roster constructions: Seattle’s “pitching-first” depth versus Houston’s star-heavy but thin lineup. Given the current injury crisis in the Astros’ clubhouse, the Mariners on the moneyline is the most disciplined play. Expect a tight affair where Bryan Woo keeps the ball in the park, making the Under 8.5 an excellent secondary target.