In a move between the St. Louis Rams and Dallas Cowboys, they will trade former first round draft picks with the Rams send offensive tackle Alex Barron to Dallas in exchange for lineback Bobby Carpenter.

Carpenter was the 18th pick of the 2006 draft for the Cowboys, and Barron was a first round pick of the Rams in 2005. He started 74 of 76 games, but led the NFL in holding penalties last year.

Barron will battle Doug Free for the starting left tackle spot. If he doesn’t win the job, he will be a backup who can play the left and right side of the line.