The New York Yankees are expected to be without closer Luke Weaver for at least a month after he injured his hamstring while warming up during Sunday night’s game against the Los Angeles Dodgers.

ESPN reports Weaver will be put on the injured list Tuesday and miss 4-6 weeks, which will put the Yankees’ closer situation in flux once again.

Weaver, who served as the Yankees closer last year during their run to the World Series, began this season as a setup man after the team acquired two-time All-Star Devin Williams in a trade with the Milwaukee Brewers.

However, Williams struggled mightily in his introduction to New York − posting an 11.25 ERA in his first 10 appearances − and Weaver reclaimed closing duties.

Weaver sports an impressive 1.05 ERA in 24 appearances this season with one win and eight saves.

Williams has pitched better lately (2-0, 1 save, 1.80 ERA in his last 11 appearances) and should return to the closer’s role while Weaver is out.