Whitlock (hip) is slated to make a 1-to-2-inning rehab appearance for Triple-A Worcester on Friday, Ian Browne of MLB.com reports.
Red Sox manager Alex Cora has already said that Whitlock will be deployed out of the bullpen upon returning from the 15-day injured list, so the right-hander may only need one or two appearances in the minors prior to being activated. Tanner Houck and John Schreiber have emerged as the top options at the back end of the bullpen, but Whitlock could still see the occasional save chance while serving as a multi-inning, high-leverage relief arm.