Buffalo Bills sign Matt Leinart and Thaddeus Lewis

The Buffalo Bills have signed quarterback duo Matt Leinart and Thaddeus Lewis following an injury to Kevin Kolb.

Kolb was forced off during his side's pre-season loss to the Washington Redskins on Saturday with what the Bills fear could be a career-threatening head injury.

His injury left the Bills short in the quarterback department, with rookie EJ Manuel also sidelined for at least the rest of pre-season having undergone surgery on a knee injury.

Leinart, a former first-round draft pick, joins his fourth different NFL franchise having been a free agent since leaving the Oakland Raiders during the off-season.

Lewis, meanwhile, joins the Bills from the Detroit Lions in a trade that sees linebacker Chris White go the other way.