BOSTON -- With Josh Beckett still getting back on his feet following an illness that knocked him out of his start earlier this week, the righty will pitch next on Tuesday night, when the Red Sox open a three-game series against the Phillies.

Beckett had been penciled in for Saturday at Pittsburgh, but manager Terry Francona made the adjustment during Thursday's off-day.

Veteran knuckleballer Tim Wakefield will now pitch Saturday, followed by lefty Andrew Miller on Sunday.

In addition, the Red Sox announced that reliever Bobby Jenks, who has been on the disabled list with a sore upper back, will begin a Minor League rehab assignment on Saturday for Double-A Portland.