Starting right tackle Brad Butler was helped off the practice field Tuesday after suffering a lower back injury.

"Brad hurt his low back in a drill," Jauron told the Buffalo News. "(Trainer) Bud (Carpenter) took him in and examined him. We'll see where it goes. He (Carpenter) is optimistic it's not a long-term thing."

With Butler sidelined, Buffalo shifted the versatile Kirk Chambers to right guard. Chambers started four games last year at both guard and tackle.

Buffalo needs Butler to transition well to right tackle for the line to gel. After losing Jason Peters, the team moved Butler to the outside and slid Langston Walker to left tackle.

Earlier this off-season, Butler talked to BuffaloFootballReport.com all about the switch in this feature.

And for a premium Q & A with Butler, click here.

In other news, cornerback Leodis McKelvin sat out Monday and Tuesday morning's practices with a quadriceps injury. Free agent Drayton Florence stepped in as starter in his absence.