The Giants announced the roster moves Saturday. They also re-signed quarterback Ryan Perrilloux to the practice squad for the sixth time this season.
Clayton, who will have surgery Monday for a torn meniscus in his knee, is an eight-year veteran who was among the team's final cuts this year. He was re-signed Sept. 23 and played in five games, mostly on special teams.
Trattou, a rookie free agent from Florida, also was among the final cuts. But he was re-signed and played in the Giants' season opener, recording a tackle. He was released four days later and re-signed to the practice squad.