Adam Warren placed on the 10-day disabled list
Warren, 30, owns a 2.40 ERA on the season with 53 strikeouts in 56 1/3 innings of work.
The six-year veteran has been a reliable component of the Yankees bullpen all year long, and during a 24-game stretch from May 27 to August 16, Warren allowed just two earned runs over a total of 27 2/3 innings pitched (0.65 ERA).
Warren has been used solely out of the bullpen since he rejoined the Yankees last season in a trade with the Cubs, but over his first four MLB seasons, all with New York, Warren served as a versatile swingman capable of making spot starts and eating innings effectively.
Per Bryan Hoch of MLB.com, Warren had been experiencing a lower back issue since Sunday, and the plan for him is to rest for the next two weeks as the Yankees make a late push toward the postseason.
Following Wednesday's rain-out, the Yankees will play the final game of their three-game series against the Orioles at 1:35 PM Thursday in Baltimore.