Pettigrew did not practice Wednesday, and the team has not yet disclosed the nature of his injury. Williams had arthroscopic knee surgery in August and has not yet played this season.
CBS also reported that safety Louis Delmas was a participant in practice Tuesday. Delmas has not practiced since having surgery in August on his knee. The list of players who sat out last week's practices and participated Tuesday includes center Dominic Raiola, safety John Wendling, end Cliff Avril, linebacker Stephen Tulloch, and cornerback Bill Bentley.
The 1-3 Lions visit the 3-2 Philadelphia Eagles on Sunday, Oct. 14 in a 1 p.m. ET game broadcast on Fox.