UPDATE 10:55 p.m. ET: Grimes told ESPN's Josina Anderson his new contract is for four years.
UPDATE 11:29 p.m. ET: The four-year deal is worth $36 million with $16 million guaranteed, according to ESPN's Adam Schefter.
"I wanted to be back but you never know in this business and when it all worked out I was happy," Grimes told Anderson moments after the news broke."
The deal was expedited by the impending Monday afternoon franchise tag deadline. Had the Dolphins been unable to lock Grimes down with a long-term contract, they were mulling the possibility of using the tag to keep him in Miami for at least one more season.
As Dolphins blog The Phinsider explains, Grimes's four-year deal may be more of a two- or three-year deal in practice.
Most deals that are labeled as "four-year deals" in the NFL tend to be two- or three-year deals in practice because the guaranteed money is usually contained in the signing bonus and base salaries of the first two years. Depending on how much guaranteed money is in the deal, therefore, a player signing a four-year deal usually becomes a viable cap casualty (a player who can be cut to gain cap space) no later than the third year of his deal.
Few teams had more money to spend entering the offseason. The Dolphins came in with more than $30 million in estimated cap space, making the continued relationship with Grimes an easy choice. With coach Joe Philbin entering his third season in Miami, the team is in must-make-the-playoffs mode, something the franchise hasn't done since 2008.
Grimes, 30, spent his first six NFL seasons with the Atlanta Falcons before coming over to Miami before the 2013 campaign. Grimes bounced back after playing only one game in 2012 because of an Achilles injury, starting in all 16 games for Miami.
Grimes is coming off his second trip to the Pro Bowl, his first coming back in 2010. According to Pro Football Focus, only Darrelle Revis outperformed Grimes in 2013 at the corner position. Grimes posted four interceptions and 16 pass deflections.
The Dolphins really could not afford to let Grimes walk, considering the lack of depth they have at the cornerback position. Across from him is Nolan Carroll, who ranked 52nd on PFF. Beyond him, Miami has Jamar Taylor and Will Davis, who both provide decent services as backups but are not starting material at this point.
Here's The Phinsider on the re-signing:
This move is significant for two reasons. First, it means the Dolphins have a playmaking, No. 1 cornerback under contract for the next couple of years to give the Dolphins some stability at the cornerback position. Grimes, who was playing under a 1-year, $5 million contract, was rated as the second best cornerback in the NFL in 2013 by Pro Football Focus, behind only some guy named Darrelle Revis who was getting paid $16 million a year. Second, it leaves the Dolphins the option to use the franchise tag on another player before today's 4 p.m. deadline.