Although the Lions were one of eight teams to attend Kaepernick's workout last month. the team will not be adding the quarterback to its roster. The Lions signed Kyle Sloter from the Arizona Cardinals' practice squad. and added Joe Callahan to the practice squad on Saturday. Jeff Driskel was placed on injured reserve. and Matthew Stafford has missed four straight games due to a fractured back. Kaepernick worked out in front of eight teams in Atlanta in November. The Lions, Eagles, Chiefs, Jets, Redskins, 49ers and Titans all attended the workout, according to Kaepernick's agent Jeff Nalley. Kaepernick has yet to receive a call from any of the teams who attended the workout.