"Detroit Lions quarterback Matthew Stafford is day-to-day with a knee injury, coach Jim Schwartz said today.

Schwartz declined to comment on reports that Stafford suffered a dislocated kneecap during Sunday's 48-24 loss at Chicago. He said only that Stafford had completed medical testing and the Lions would know more about his status when they resume practicing Wednesday.

Asked whether Stafford needed to practice by Wednesday or Thursday to play Sunday against Pittsburgh, Schwartz said he would not place a deadline on it.

Schwartz also said Derrick Williams will take over kickoff returns from fellow rookie Aaron Brown, who has struggled the past three games. Williams, a third-round pick, was drafted mostly for his special teams ability but struggled during the exhibition season."