Cowboys sign two offensive linemen

OXNARD, Calif. -- The Cowboys signed two offensive linemen, guard Jeff Olson from TCU and tackle James Nelson from UT-El Paso, on Thursday.

To make room on the 90-man roster, the team cut defensive end Cameron Sheffield and cornerback Devin Smith. Sheffield was battling a groin injury that was going to keep him out a few weeks.

Six Cowboys offensive linemen are hurt, so Dallas had a shortage of natural guards available for Sunday's preseason opener against the Miami Dolphins.

Olson was released by Tampa Bay on Monday.

Nelson has an impressive arm length of 36 1/2 inches, which is longer than Luke Joeckel's 34 1/4-inch arms. Joeckel was the No. 2 pick of the 2012 NFL draft by Jacksonville.