Wheels Fall Off for Mariners Top Prospect Kade Anderson in MLB Debut

Seattle Mariners left-handed pitching prospect Kade Anderson made his first start in the big leagues on Saturday. And while the 22-year-old looked sharp early in his MLB debut, he ran into trouble in his final inning.

Anderson, MLB Pipeline's No. 5 overall prospect for 2026, came one out away from completing six innings in the Mariners' 5-4 victory over the Chicago Cubs on Saturday. The young southpaw allowed three runs in 5 2/3 innings on five hits and two walks, while striking out five in a game Seattle eventually won on a walk-off two-run homer by Randy Arozarena.

After tossing four scoreless frames to start the evening, Anderson surrendered his first run in the fifth inning on a sacrifice fly. Then, the 6-foot-2 lefty gave up back-to-back solo shots to Alex Bregman and Michael Busch in the sixth inning before exiting the game to a standing ovation from the Seattle crowd.

Evaluating Kade Anderson's MLB debut and what's next for Mariners southpaw

Aug 22, 2026; Seattle, Washington, USA; Seattle Mariners starting pitcher Kade Anderson (13) takes the mound before a game against the Chicago Cubs at T-Mobile Park. Mandatory Credit: Joe Nicholson-Imagn Images | IMAGN IMAGES via Reuters Connect

Overall, Anderson lived up to the hype early on in his MLB debut. But it seems like the Mariners may have left the young hurler in the game a little too long. As The Seattle Times' Adam Jude pointed out, the 22-year-old's highest pitch count in the minors this year was 80 back in June. The left-hander entered the sixth inning at 72 pitches and then gave up the back-to-back home runs on his 80th and 81st pitches of the evening.

Regardless, the Mariners are likely still encouraged by what they saw from Anderson on Saturday. He faced the team that currently holds the National League's top Wild Card spot and mostly kept them in check until the end of his outing. And the No. 3 overall pick in the 2025 MLB Draft did so after pitching in just 18 Double-A games before his first start in the majors.

It would be somewhat surprising if Seattle sent Anderson back down to the minors after just one start, so he'll likely toe the rubber again in the big leagues next week. But it will be interesting to see how the Mariners handle the young hurler's workload the rest of this season, especially after the Cubs did most of their damage on the final pitches of the lefty's MLB debut.

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