Mets Swap Bullpen Arms, Elevate Stock for Marlins Start

The Mets executed a 40-man roster shuffle Sunday, designating right-hander Kevin Herget for assignment and selecting Bryce Conley to the active roster. The transaction clears space for Robert Stock, who takes the mound today against Miami in a spot start. Jonathan Pintaro was optioned to Triple-A to create the corresponding bullpen slot.

Herget's departure reflects a season-long drift for the veteran reliever. His inability to hold leverage innings—he posted a 4.82 ERA across 56 games entering Sunday—made him expendable in a rotation-first bullpen architecture. Conley, a prospect with upside as a velocity-and-movement play, gets his first major-league opportunity at the tail end of August, suggesting the Mets are comfortable cycling younger arms into the relief mix rather than doubling down on aging depth.

Stock's elevation for the start signals a different kind of message: the Mets lack confidence in their fifth-starter pipeline or are managing workload for a starter currently in the rotation. Without the full context of who Stock replaces or whether an injury prompted the move, the precise mechanism remains unclear. However, roster churn at this late-season point—nearly two months from the regular-season finish—typically tracks with teams either punting on the stretch run or aggressively experimenting with bullpen construction ahead of September callups.

For bettors, the Herget designation removes a middle-reliever option from New York's leverage pool, which matters if the Mets face leverage situations in tight games. His replacement, Conley, is an untested commodity with no MLB track record; market makers haven't priced his appearance into reliever prop markets yet because he had no major-league presence to model. If Conley takes high-leverage innings before the market fully incorporates his volatility, early-game bullpen decisions (first-inning walks, strikeouts by the primary reliever group) may shift odds before the sharps adjust. This is a single-event calendar entry—it carries weight only if Conley debuts in a pivotal spot or if the Mets' bullpen usage patterns shift visibly within the next 48 hours.