Mariners Plan to Call Up Kade Anderson, Top Pitching Prospect, to Start Saturday

The Seattle Mariners are planning to call up left-hander Kade Anderson to start Saturday, per ESPN's Jeff Passan, who cited sources. Anderson is regarded as the top pitching prospect in baseball.

The numbers Anderson is bringing from the minors are not subtle: a 1.06 ERA over 93.1 innings, 135 strikeouts, 13 walks, and 47 hits allowed. The third pick in the 2025 draft, he has done very little to suggest the minor leagues have been a fair fight.

What remains unconfirmed

Passan's report is sourced, not a club announcement — the promotion has not been formally declared by Seattle. The specific opponent, roster move required to create a spot, and any role beyond Saturday's start are not addressed in the report.

The backdrop

The timing is hard to miss. The Mariners were routed 22-0 by the Brewers — a result that, per prior Posterior reporting, tied the MLB record for most lopsided shutout loss in history. That game saw a position player take the mound and a bases-loaded error late, leaving Seattle's rotation picture a matter of some urgency. Anderson, if the call-up proceeds as reported, would step into that context.

Matt Brash has also been working his way back, having thrown a bullpen session from the mound with a possible September return in view, per earlier reporting. Anderson's expected arrival would represent a different kind of reinforcement — a prospect debut rather than a rehab return.