The Patriots signed second-round picks CB Ras-I Dowling and RB Shane Vereen on Tuesday.
The team also released QB Jonathan Crompton, a fifth-round pick by the Chargers in the 2010 draft. He finished the '10 season on the Patriots' practice squad.
Dowling, a physical corner, is expected to challenge for playing time in the team's nickel. Vereen will be in the RB rotation.
The Pats also added free-agent DE Christian Cox, a rookie out of Utah.