And it's unclear whether Edwards will be healthy in time to play next weekend when Buffalo hosts Miami at Toronto.
"As of right now, I have no idea," Edwards said. "We're going to have to re-evaluate it again tomorrow."
Edwards characterized the injury as either a pull or a strain.
"It is unfortunate. It's frustrating," he said. "And I need to get in the training room and get better."
Edwards went 10-of-21 for 112 yards before being replaced by J.P. Losman for the start of the second half.
Edwards said his groin began bothering him at the start of the game and that the pain became more severe every time he was knocked down. The worst came after the final play of the second quarter, when Edwards rolled to his right and completed a 24-yard pass to Josh Reed along the right sideline as time ran out.
"It really kind of put it over the top," Edwards said. "We made the call to just shut it down."
Edwards spent the second half watching from the sideline wearing a black rain coat and with a wool cap pulled over his head.
The Bills (6-6) lost for the fifth time in six games and continue to sink further out of playoff contention after a 4-0 start.
Losman finished 11-of-17 for 93 yards in his third appearance this season.
Copyright 2008 by The Associated Press