The Dolphins gave their fans hope by winning six of their final nine games to end the 2011 season and built on that faith this offseason by making several key additions. Here are the three biggest.

Richard Marshall, defensive back -- The seven-year veteran is regarded as one of the top nickelbacks in the league, as he has finished in the top 10 in tackles among defensive backs each season of his career. Marshall’s coverage skills also have improved, as he defended 11 passes to go along with 78 tackles, three interceptions and two sacks last season. The secondary got better the minute he inked his free-agent deal.

Olivier Vernon, defensive end -- The third-round pick out of Miami reportedly was one of the stars of the team’s offseason workouts and a strong showing in training camp could lead to a starting spot in a new, 4-3 scheme. Many thought he should have stayed in school another year after starting just three games due to team issues, but his talent is undeniable. Now, the Dolphins need to get him signed so he doesn’t miss any training camp.

B.J. Cunningham, receiver -- The sixth-round pick is Michigan State’s all-time leader in receptions (218), receiving yards (3,086) and ranks second in TD receptions (25). And with Davone Bess and Brian Hartline the only established receivers on the depth chart, it gives Cunningham a chance to win not just a roster spot in training camp but also earn substantial playing time.

For more up-to-the-minute news and analysis on the Miami Dolphins from blogger Dave Carey, follow @CBSSportsNFLMIA.