Coach Dick Jauron listed Losman as day to day, but noted the quarterback will be placed on the physically unable to perform list. Losman can be activated off the list at any time.

"It won't have a lot of impact. Hopefully, it'll be very short-lived and he'll be right back on the field," Jauron said after the team held its first practice in suburban Rochester. "I don't know if deflating is a good term. I don't feel deflated. But it wasn't expected, that's for sure. These things, as we know, happen."

Losman was experiencing a little stiffness, but added he would be able to play if the Bills had a game this weekend. He said he was more embarrassed to miss the start of camp from doing leg squats on Tuesday.

"It's my fault. I was just probably a little too excited, too energetic to get going to camp," Losman said, noting he was hurt while . "We're being extra cautious. We're looking to get out there pretty soon."

Wearing his practice jersey and sweat pants, Losman watched from the sideline and did not take part in any individual or team drill. Backup Craig Nall and rookie third-round draft pick Trent Edwards took most of the snaps during the two-hour session.

The Bills hold two-a-day sessions through Saturday, before going to a single practice routine for the rest of camp, which runs through Aug. 22.

The injury is a minor setback for a player who was eager to pick up where he left off last season, when Losman won the starting job out of training camp and showed enough progress to keep the No. 1 job heading into this year.

The second of Buffalo's two 2004 first-round draft picks, Losman went 5-4 down the stretch to help the team finish 7-9 last season. Besides producing two fourth-quarter comeback victories in the last half, Losman and the offense found its rhythm by producing 17 of its 28 touchdowns over the final seven games.

The Bills are expecting even more from their offense this year after spending the offseason bolstering the line and because of Losman's development.