The Buffalo Bills began a week's worth of practices for this weekend's game against the San Francisco 49ers without free safety Jairus Byrd on the field. Though the fourth-year safety missed a large chunk of the second half of Sunday's loss to New England with a hip pointer, head coach Chan Gailey told reporters that Byrd will likely be back to practice on Thursday and play on Sunday.

Also sitting for Buffalo on Wednesday were offensive linemen Cordy Glenn and Kraig Urbik, who are dealing with ankle sprains and are expected to miss at least two weeks each. Chris Hairston and Chad Rinehart will replace them in the starting lineup on Sunday. Veteran defensive tackle Spencer Johnson also missed practice on Wednesday.

Fred Jackson and C.J. Spiller both practiced after making it through Sunday's loss largely unscathed following injuries to the knee and shoulder, respectively. It's not yet clear if either is any closer to 100 percent, but both are expected to practice this week and play in San Francisco.

Wide receiver Ruvell Martin, who has missed each of the past two games, also returned to practice on Wednesday. If he's healthy by Sunday, he'll likely dress and resume his role as one of the team's primary gunners on the punt coverage team.