Miami also released cornerback Dimitri Patterson on Monday. Patterson was plagued by injuries the past two seasons, and his release frees up more than $5 million in salary cap space for the Dolphins.
Delmas started 15 games in 2013 and had a career-high three interceptions. The South Florida native was a second-round draft pick who made 64 starts for the Lions.
''He is leader on and off the field and has a proven track record of playmaking that will benefit the entire defensive unit,'' new Dolphins general manager Dennis Hickey said.
The Dolphins are expected to be active in free agency beginning Tuesday. Their priority will be to revamp an offensive line that had an awful 2013 both on and off the field, and became the focus of a bullying scandal that sabotaged the season.
Guards Richie Incognito and John Jerry, both implicated in the scandal, are among those who become free agents. Neither is likely to return to Miami.
Help for the defensive front seven will also be on Hickey's shopping list. Nose tackles Paul Soliai and Randy Starks can become free agents, and the Dolphins also want to upgrade their linebacker corps.
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