Kirksey (hamstring) announced Thursday that he has decided to retire from the NFL, Mike Garafolo of NFL Network reports.
Kirksey, who was on Buffalo's practice squad, will hang up the cleats after nine seasons in the NFL. The 2014 third-round pick played for the Browns from 2014-19 and also spent time with the Packers and Texans. To fill his spot, the Bills are signing A.J. Klein to the practice squad.