The Seattle Mariners host the Athletics on Saturday, September 5, 2026, at T-Mobile Park with first pitch scheduled for 9:40 PM ET. George Kirby takes the mound for Seattle against left-hander Jeffrey Springs in a regular season matchup that carries late-summer weight. With the calendar pushing deep into September, every game in the standings matters, and the Mariners will look to protect home turf in front of what figures to be a loud T-Mobile Park crowd. This one airs on NBCSCA and Mariners.TV, with radio coverage on Seattle Sports 710 AM.

Pitching Matchup: George Kirby vs. Jeffrey Springs

Kirby is the story on the mound tonight. The right-hander has established himself as Seattle's most reliable arm, defined by elite strike-throwing and the kind of steady presence that gives a pitching staff a backbone. He does not beat himself — that has been the consistent truth of his game — and against an Athletics lineup, limiting free passes will be critical.

Springs draws the start for Oakland. The left-hander is a capable arm capable of generating weak contact and working through lineups with deception. Seattle's lineup will need to be disciplined against him early, work counts, and resist the urge to chase.

Seattle Mariners Starting Lineup

• 1. Randy Arozarena — LF
• 2. Dominic Canzone — RF
• 3. Julio Rodríguez — CF
• 4. Cal Raleigh — C
• 5. Josh Naylor — 1B
• 6. J.P. Crawford — SS
• 7. Taylor Ward — DH
• 8. Cole Young — 2B
• 9. Weston Wilson — 3B

Keys to Watch

Julio Rodríguez in the Middle of the Order

Batting third, Rodríguez is the engine of this offense. When he is driving the ball and forcing pitchers to work carefully, it creates opportunities for Cal Raleigh and Josh Naylor behind him. The two-three-four stretch of Rodríguez, Raleigh, and Naylor is where this game could be decided.

Cal Raleigh's Presence Behind the Plate

Raleigh hitting cleanup tells you everything about how this organization views him. He is a dual threat — a catcher who can change a game with one swing and who frames and calls a game for Kirby. His relationship with Kirby on the mound is one of the more underrated dynamics in Seattle baseball.

Top of the Order Setting the Table

Randy Arozarena leading off gives Seattle a genuine threat from pitch one. Dominic Canzone batting second adds another contact-and-on-base dimension before Rodríguez comes to the plate. If Arozarena gets on base early, Springs will feel pressure immediately.

Cole Young and Weston Wilson at the Bottom

The eight-nine spots of Young and Wilson are worth tracking. Young brings youth and athleticism at second base. Wilson at third rounds out a lineup that can manufacture runs even when the middle of the order goes quiet.

Prediction

Kirby at home in September is a strong hand to play. He controls the strike zone, limits damage, and gives Seattle a legitimate chance to win every time he takes the ball. Springs is a tough matchup stylistically, but the Mariners lineup has the depth to find a way through. Look for a competitive, low-scoring game that Seattle edges out on the strength of Kirby's performance and a key hit from the middle of the order. Mariners win, 3-1.