IRVING, Texas – The Cowboys have added some much-needed depth and experience to the interior offensive line by trading for Ryan Cook, a seven-year veteran who can play center, guard and tackle. The Cowboys sent a 2013 seventh-round pick to Miami for Cook, who wasn’t likely to make the Dolphins’ squad after Friday’s roster cuts.
Cook arrives in Dallas to provide the Cowboys with another veteran inside, but what one that can play center and backup starter 
A second-round pick of the Vikings in 2006, Cook has 40 career starts, mostly at right tackle, but has also started at guard. In fact, Cook was the Dolphins’ starting center against the Cowboys in Wednesday’s preseason finale at Cowboys Stadium.
The Cowboys obviously need some help at center, considering the rash of injuries that have occurred at the position since training camp. Costa has been bothered by a nagging back injury that forced him out of three preseason games, while backups Bill Nagy and
Arkin started the first three preseason games at center, a position he never played until training camp. If he is released because of this move, the Cowboys would likely try to retain him on the practice squad. A fourth-round pick in 2011, Arkin has not played in a regular-season game, after being inactive for all 16 last season.
