Kade Anderson's MLB debut for Mariners was a mixed bag

Kade Anderson. IMAGN IMAGES via Reuters Connect

Kade Anderson's MLB debut for Mariners was a mixed bag

By Vanessa Serrao | Last updated Aug 22, 2026 9:53 PM ET

Seattle Mariners' No. 1 pitching prospect Kade Anderson made his long-awaited MLB debut on Saturday night against the Chicago Cubs.

It was a lefty-on-lefty matchup with the 22-year-old third overall pick in the 2025 draft up against 30-year-old veteran southpaw David Peterson at T-Mobile Park. A surprise change for a Mariners roster that has heavily relied on right-handed starting pitching.

Looking to dominate just as he seamlessly has in the minors, Anderson was up against one of the hottest lineups with the Cubs and playing for a Mariners team that is fighting for an AL wild-card spot. The Cubs got a fresh look with MLB Pipeline's No. 5 prospect, and he got his first big-league strikeout against Alex Bregman along with a scoreless first inning.

Then in the bottom of the first for the Mariners, Randy Arozarena crushed a lead-off home run and provided Anderson with an early 1-0 lead. But Arozarena wasn't done helping out the rookie, who in the top of the third inning took a home run away from Miguel Amaya.

Anderson didn't give up a lot of hard contact early in the game and provided five scoreless innings until Cubs' Kevin Alcantara hit a sacrifice fly in the top of the fifth to tie the game.

Then in the top of the sixth inning, the Cubs offense came alive as back-to-back home runs were hit by Bregman and Michael Busch, which ended Anderson's night. He finished his debut pitching five and 2/3 innings with five hits, three earned runs, two walks, five strikeouts and 83 pitches thrown.

Breggy and Busch go back-to-back off Kade Anderson! pic.twitter.com/rqL7OYntKS
— SleeperMLB (@SleeperMLB) August 23, 2026

Kade Anderson dominates early, but then the Cubs' power chases him

Anderson was dominant across five innings, but once he got through the Cubs' lineup for the third time, they figured him out, and he was no match for the red-hot Bregman, who crushed his 19th home run of the season and his seventh in August. Both Bregman and Anderson both attended Louisiana State University, which made the at-bats all the more compelling.

Before the back-to-back home runs, Anderson had retired Pete-Crow Armstrong twice, but then the third time he faced him, PCA hit a double off the wall. But then the double was erased as the Mariners got PCA tied up between second and third, and what looked like a promising inning backfired. Despite the downfall of the sixth inning, Anderson exited the game gaining a standing ovation from the crowd.

Overall, Anderson's emotions were riding high, and while his night didn't end how he wanted it to, he provided a solid debut for the Mariners.

Vanessa Serrao

Serrao is a freelance baseball writer who has covered all MLB teams, with particular expertise on the Toronto Blue Jays. She is a member of the Internet Baseball Writers Association of America.

More must-reads: