The Miami Dolphins continue to add pieces to their already stout defense.

On the same day they brought back Pro Bowl defensive tackle Paul Soliai, Miami also agreed to a three-year, $16 million contract with free-agent cornerback Richard Marshall, according to ESPN's Adam Schefter. Marshall started nine games for the Arizona Cardinals last season and recorded four interceptions.

Marshall was in Miami for a visit Wednesday and tweeted the Dolphins wouldn't let him leave without an agreement. He will add depth to an already talented secondary that includes starting corners Vontae Davis and Sean Smith. New Miami defensive coordinator Kevin Coyle was a longtime defensive backs coach with the Cincinnati Bengals. Coyle knows how important it is to have at least three solid cornerbacks.

The Dolphins have been coy about their plans on defense this offseason. There has been speculation that Miami might consider moving Smith to safety next season, in part because there is a need and also because Smith has the size to play the position. I don't think that's the case, but this Marshall signing at least gives the Dolphins the flexibility. He can also play safety if needed.

The cornerback trio of Davis, Smith and now Marshall should make Miami's defense formidable against three-receiver sets.