Kolarek was optioned to Triple-A Durham following Wednesday's loss to the Yankees, Juan Toribio of MLB.com reports.
The Rays will swap Kolarek out for a fresh bullpen arm (Austin Pruitt) ahead of Thursday's series opener after Wednesday's starter, Blake Snell, lasted just one out. Kolarek pitched 1.1 innings of relief in Wednesday's 12-1 loss, allowing three runs on one hit and two walks while striking out three.