Whitlock (knee) will embark on a rehab assignment with Triple-A Worcester on Saturday, Tim Healey of The Boston Globe reports.
Whitlock is ready to take the next step in his recovery from left knee inflammation that led to him being placed on the 15-day injured list in late May. Red Sox manager Chad Tracy relayed that how Whitlock's knee reacts following Saturday's Triple-A game will determine whether the right-hander will need just one rehab outing before being activated from the IL.