The Buffalo Bills placed quarterback Kevin Kolb (concussion), receiver Brad Smith (chest) and fullback Drew Smith (undisclosed) on injured reserve Friday.

As previously reported, Kolb's head injury is career threatening.

The Bills also released 18 players to make room for the mandatory 53-man roster each team has to cut down to by Saturday at 6 p.m. Those cuts were DE Kourtnei Brown, RB Zach Brown, DB Crezdon Butler, G Antoine Caldwell, G Zack Chibane, DB Jordan Dangerfield, TE Dorin Dickerson, DB Kip Edwards, RB Kendall Gaskins, DT Jarron Gilbert, DB T.J. Heath, WR Brandon Kaufman, QB Matt Leinart, LB Keith Pough, TE Nick Provo, T Zebrie Sanders, LB Brian Smith and C David Snow.

The Bills have 55 players left on the roster and need to make two more moves by Saturday at 6 p.m., the NFL's roster deadline.

Follow me on Twitter: @RavensInsider

Aaron Wilson covers the Ravens for The Baltimore Sun.