The Jets signed veteran S Gerald Alexander on Tuesday, one day after placing S Jim Leonhard on injured reserve.
Alexander, a fifth-year vet, played in two games for the Dolphins earlier this season. He split the 2010 season with the Panthers and Jaguars and began his career in Detroit. As a rookie, Alexander started all 16 games for the Lions and had two picks.
Brodney Pool will start opposite Eric Smith in Leonhard's place. Alexander will likely be the team's No. 3 safety.
The Jets currently hold the final playoff spot in the AFC. Alexander confirmed the signing on his Twitter.