The Dolphins acquired Cook, who was the Vikings' 2006 second-round pick, off the waiver wire last year and he played center and guard for the team in 2011. But Cook was beaten out by rookie Josh Samuda, an undrafted prospect from UMass, for the backup center spot.
Samuda, a Hollywood Hills product, was one of camp's most pleasant surprises, and is expected to make Miami's 53-man roster today.
Cook, who has started 40 NFL games, spent most of camp as the third-team center and never manned the guard spot, which happens to be Miami’s weakest area. But he did surprisingly start Wednesday night's 30-13 loss to Dallas, which was clearly an audition.
Cook was slated to earn $1 million this season, but moving him clears all but $100,000 from Miami’s books.
The Cowboys have been struggling with their depth this camp because of numerous injuries to key reserves, which include center Phil Costa, who has been limited by a back injury.
The Cook trade now means the Dolphins could have multiple picks in the second, third, seven and possibly the sixth-round (it is conditional) of the 2013 NFL draft because of trades involving Brandon Marshall and Vontae Davis.