Carpenter-for-Barron trade close?

IRVING, Texas -- The Dallas Cowboys are shopping linebacker Bobby Carpenter, a team source told ESPNDallas.com's Calvin Watkins.

The St. Louis Rams are among the teams that have expressed interest in Carpenter, the Cowboys' 2006 first-round pick.

League sources told ESPN NFL Insider Adam Schefter that the Rams are on the verge of sending offensive tackle Alex Barron to the Cowboys. Barron, a first-round draft pick in 2005 who has often struggled as the Rams' starting left tackle, is a restricted free agent who has not signed his first-round tender offer.

Carpenter's role with the Cowboys essentially disappeared when they traded up to draft Penn State linebacker Sean Lee in the second round. The Cowboys, who gave Lee a first-round grade, plan for the rookie to replace Carpenter in the nickel and dime packages.

Dallas owner/general manager Jerry Jones has expressed confidence that Doug Free is ready to replace longtime left tackle Flozell Adams, who was released this offseason. However, depth behind Free is a concern that could be addressed by adding Barron.