David Arkin never played a down for the Cowboys in 2 1/2 seasons. They released the offensive guard on Saturday, clearing the way for safety Jakar Hamilton to be moved up from the practice squad.Starting safety J.J. Wilcox sprained his knee in practice Thursday and will miss at least this week’s game against the Lions, necessitating the move with Hamilton, who is an undrafted free agent from South Carolina State. Rookie Jeff Heath will make his first career start Sunday.Arkin was a fourth-round pick in 2011. He was inactive for all 16 games as a rookie and inactive for nine games in 2012 and six games this year. He did not play in the eight games he has been active.The Cowboys could sign Arkin to the practice squad if he clears waivers.Briefly • European games: Commissioner Roger Goodell said in London that the NFL’s overseas success doesn’t mean the Super Bowl is crossing the Atlantic or that the league is going back to continental Europe. • Seahawks: Percy Harvin’s debut with Seattle will have to wait at least another week. The receiver, coming off hip surgery in April, won’t play against the Rams on Monday night, coach Pete Carroll said. Harvin practiced last week for the first time.