Yarbrough is expected to serve as a bulk reliever behind opener JT Chargois in Thursday's game against the Blue Jays, Marc Topkin of the Tampa Bay Times reports.
Since being called up from Triple-A Durham on Aug. 30, all three of Yarbrough's appearances have come out of the bullpen on days the Rays have deployed openers. In those outings, Yarbrough has gone 1-0 with an 0.84 ERA, 1.13 WHIP and 6:3 K:BB in 10.2 innings. The Rays may continue to deploy him as a bulk reliever so long as the arrangement keeps yielding quality results.