OXNARD, Calif. -- The most experienced offensive lineman on the Dallas Cowboys’ roster is fighting for a spot on the team.

Guard Derrick Dockery has 113 career starts, but only four of those came in the last two years. He was out of work until the Cowboys, hit by a rash of injuries to guards, signed him last week.

However, don’t assume that the 6-foot-6, 325-pound Dockery is just a camp body. He’s competing for a backup job.

There are three guards who are virtually guaranteed roster spots: free agent additions Nate Livings and Mackenzy Bernadeau and undrafted rookie Ronald Leary. Livings and Bernadeau were given eight-figure contracts with significant signing bonuses to be starters, and the Cowboys liked Leary enough to guarantee $214,000 of his salary.

That likely leaves Dockery battling David Arkin for a roster spot.

Arkin, a fourth-round pick last season, has the advantage of being younger and cheaper. Dockery has the edge of being more experienced and ready to play.

“I love Dock,” offensive coordinator/line coach Bill Callahan said. “I saw him on film when he played last season against the Giants and also against the 49ers, and I liked what I saw. This is really positive. He’s encouraged about his opportunity and we had a good, long talk about what he needs to get done and how he can improve himself. He’s very willing and very motivated to do a great job for us.”

The decision could be influenced by the health of Bernadeau (just started practicing after recovering from hip and knee surgeries) and Livings (out with a strained hamstring). If their durability is in doubt, it’d make sense for Dallas to keep a guard who has been in the battles before.