Cubs vs Mariners Lineup: No Ian Happ, Alcantara Starts, an MLB Debut, More

The Chicago Cubs are set to take on rookie Mariner Kade Anderson in his MLB debut.

Aug 21, 2026; Seattle, Washington, USA; Chicago Cubs right fielder Seiya Suzuki (27) runs towards first base after hitting a single against the Seattle Mariners during the seventh inning at T-Mobile Park. Mandatory Credit: Steven Bisig-Imagn Images | IMAGN IMAGES via Reuters Connect

The Chicago Cubs dropped their Friday night matchup with the Seattle Mariners 6-5 in the 10th inning after Leo Rivas' walk-off RBI single. Despite two home runs from Alex Bregman, including the game-tying solo homer in the top of the 9th, the Cubs were unable to overcome a 4-run second inning by the Mariners.

The Cubs are hoping for better results in Saturday night's national game on FOX, as they'll be facing the Mariners' top prospect, Kade Anderson. David Peterson will take the mound for the Cubs as they look to snap their two-game skid and keep pace with the Brewers, who lead the NL Central by 6.5 games.

There are plenty of reasons the Cubs need a win tonight, but they'll have to go through the Mariners' top rookie to get it done.

Game Info

Who: Chicago Cubs (74-55) vs Seattle Mariners (61-68)
Where: T-Mobile Park - Seattle, WA
When: 6:15 PM CT
Watch: FOX
Listen: 104.3 The Score

Chicago Cubs Lineup

1. Pete Crow-Armstrong, CF
2. Seiya Suzuki, DH
3. Alex Bregman, 3B
4. Michael Busch, 1B
5. Nico Hoerner, SS
6. Tyrone Taylor, RF
7. Pedro Ramirez, 2B
8. Kevin Alcantara, LF
9. Miguel Amaya, C

Ian Happ will sit tonight against the left-handed Anderson, as he has a .158 average against lefties this year, meaning Kevin Alcantara will get the start in LF with Seiya Suzuki at DH and Tyrone Taylor sliding to RF. Alcantara in his eight games back at Iowa before being called up for the White Sox series at a .905 OPS with 2 home runs.

Alex Bregman has remained hot at the plate, hitting two home runs last night. He continues to build on his monster August. In 19 games this month, Bregman has 7 home runs and a 1.020 OPS – he's reached base in all but 4 of those 19 games, as well. And he's remained his patient self at the plate, walking nearly as much as he's struck out, with 9 BBs to 12 SOs.

Seattle Mariners Lineup

1. Brendan Donovan, 3B
2. Randy Arozarena, LF
3. Dominic Canzone, RF
4. Julio Rodriguez, CF
5. Josh Naylor, 1B
6. Taylor Ward, DH
7. Cal Raleigh, C
8. Cole Young, 2B
9. Leo Rivas, SS

On the Mound ...

Cubs – David Peterson, LHP

Aug 12, 2026; Washington, District of Columbia, USA; Chicago Cubs pitcher David Peterson (19) pitches against the Washington Nationals during the third inning at Nationals Park. Mandatory Credit: Geoff Burke-Imagn Images | IMAGN IMAGES via Reuters Connect

The 30-year-old Peterson has been excellent in his last 7 outings with a 2.06 ERA and 56 ground balls. In front of the Cubs' defense, that's been good for a 6-1 record coming over from the Mets. Since his first start for the Cubs, where he lasted only 3.2 innings and allowed 10 earned runs, Peterson has gone at least 5 innings in each of his next 6 starts, allowing only 3 runs or fewer.

He'll be facing a Mariners lineup that's underperformed but has a reigning MVP in Cal Raleigh and will still work counts with a 9.0 percent walk rate. Peterson just needs to keep the ball on the ground like he has all year for the Cubs and let his defense take care of the outs.

Mariners – Kade Anderson, LHP

Jul 12, 2026; Philadelphia, PA, USA; American League pitcher Kade Anderson (32) throws a pitch against National League in the first inning at Citizens Bank Park. Mandatory Credit: Kyle Ross-Imagn Images | IMAGN IMAGES via Reuters Connect

The 22-year-old top prospect currently leads all of the minors with a 1.06 ERA, 0.64 WHIP, and a .399 OPS this year, striking out 40.5 percent of the batters he's faced. The 2025 No. 3 overall pick is ranked 5th on MLB Pipeline and is likely the most anticipated pitcher debut for Seattle since Felix Hernandez got called up in 2005.

Anderson doesn't light up radar guns with a fastball that tops out at 97 mph, but his heater plays up with its late carry. And he pairs the fastball with two breaking balls, a slider and curveball that both are considered plus pitches. Anderson has potential ace stuff from the left side, and the Cubs have responded clearly with their right-handed dominant lineup.

We'll see who wins the matchup tonight, but it should be a fun atmosphere at T-Mobile Park in Seattle.

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