Whitlock (elbow) allowed one run on five hits and struck out four over four innings Tuesday in his rehab start with Triple-A Worcester.
Whitlock, who made the first of at least two rehab starts for Worcester, didn't walk a batter and threw 49 pitches (35 strikes). Pending the outcome of his next start, Whitlock could rejoin the Red Sox next week, at which point manager Alex Cora will have a decision to make. Whitlock will presumably have a starting role waiting for him, but Boston will likely have to move one of its other six rotation members to the bullpen.