Bullpens Boomed at the 2025 MLB Trade Deadline

In a season where relief pitching hasn't correlated much with winning, teams couldn’t stop trading for bullpen arms.

New Phillie Jhoan Duran was the most valuable reliever traded at the deadline.

The dust is still settling on an active 2025 MLB trade deadline that saw 171 players (across both the majors and minors) moved in the final week of July, including 123 on Deadline Day itself Thursday. There were buyers and sellers, as well as winners and losers — even if we know those might not matter as tremendously as the hype suggests. The wide-open state of this baseball season encouraged a bunch of teams to keep pushing for the World Series, and there were plenty of down-and-out squads willing to accommodate those wishes, for a price. Some teams — such as the Rays, Royals and Padres — even tried to do a little of both at various times.

Any analysis of the trade deadline needs to break down who added what and in what measure, so we’ll start by looking at Wins Above Replacement added and subtracted since July 1. (Apologies to the Giants, who snagged Rafael Devers on June 15, but mid-June is a bit outside the window for what’s typically considered “deadline” activity.) WAR is per 162 team games, and is broken down into two categories: Total 2025 WAR,¹ and a player’s “Established Level” of multi-year talent. (Established Level is just a 3-2-1 weighted average of WAR/162 in this year and the previous two.)²

Here’s a ranking of all the players on the move in that window of time: