Who replaces Rob Thomson as interim?

Don Mattingly named Phillies interim manager

The Philadelphia Phillies have named Don Mattingly as their interim manager after firing Rob Thomson.

The move came after Philadelphia got off to a disastrous start, including a 9–19 record through the early portion of the season. Thomson was removed with the Phillies tied for last place, and the organization moved quickly to install a replacement rather than extend the trial period.

Mattingly, who has served in the organization and is widely experienced as a major-league manager and coach, will lead the Phillies on an interim basis through the remainder of the 2026 season, according to the pool’s reporting.

A separate piece in the pool also emphasizes how the interim decision affects the timing of the team’s broader managerial search, with the club effectively using Mattingly as a bridge while it considers longer-term options.

Why it matters: changing managers this early typically signals that the organization views the early results as a fundamental issue—not just a temporary slump—and that it wants a different approach immediately in areas like game management, lineup decisions, and clubhouse leadership.

For fans, the transition is also notable because Thomson was previously credited with success during his tenure, including taking the Phillies to postseason runs earlier in the decade. Despite that history, the 2026 start forced the Phillies to make a decisive shift.

In short, Mattingly’s appointment is the immediate answer to the on-field underperformance, and the Phillies now operate through the season with him as the face of the dugout while the franchise’s decision-making continues behind the scenes.