The 25-year-old Posey recorded six tackles in five games with Cleveland in 2013. He started the season finale for the Browns, playing 52 snaps in a loss at Pittsburgh. The previous season, the 5-foot-11, 200-pound Posey appeared in two regular season games for the Dolphins.
Edwards (6-1, 200) also spent time with the Bills in 2013. He played collegiately at Missouri.
The Vikings have all 90 roster spots occupied.