Posted by ESPN.com's Tim Graham
Opposing receivers better keep their heads on a swivel.
Bell signed a four-year, $20 million contract with $10 million in guarantees, a league source informs ESPN.com. He will remain Miami's strong safety.
Wilson will move to free safety, the position he played for the New York Giants when they won the Super Bowl. He has played strong safety every other year in the NFL, including last season with the Oakland Raiders.
Bell and Wilson combined to make 249 tackles last year. Bell led the Dolphins with 120 tackles, including 100 solos.
Wilson was second for the Raiders with 129 tackles.
Thursday's signings give Miami three-quarters of its defensive backfield. Three of last year's starters were headed to free agency.
Renaldo Hill, last year's free safety, appears to be the odd man unless he wants to accept backup money to re-sign with the Dolphins.