Cardinals center Earl Watford snaps to quarterback Carson Palmer during a recent OTA.

Honestly, Earl Watford had never given much thought to playing center.

Then, this offseason before the Cardinals returned to the practice field for organized team activities and the offensive lineman was on his own, it was pretty much all he worked on.

The Cards did have a vacancy at the position, although the team drafted Evan Boehm and had veteran A.Q. Shipley who had started there. While coach Bruce Arians said Watford too has a chance to win the job, Watford's efforts are more about helping himself win a job in an area with many question marks in June: The reserves on the offensive line.

There are three offensive line starters set with left tackle Jared Veldheer, left guard Mike Iupati and right guard Evan Mathis. Right tackle will be D.J. Humphries' to lose. Center looks destined to come down to Shipley versus Boehm.

Beyond that, though, is inexperience. Watford did start two games for the Cardinals at right tackle last season in place of Bobby Massie last year, but other than that, the roster is dotted with prospective backups who still must prove themselves.

"It's still a learning process," offensive coordinator and line coach Harold Goodwin said. "At the end of the day we're going to need seven bodies and right now I have a pretty good clue who five are, but I don't know who six and seven are going to be.

"It's all about the shoulder pads. Everybody looks good in shorts. Even I look skinny."

Arians likes dressing only seven linemen on game days, so versatility matters. That's why Watford wanted to work at center. Already in the brief offseason work, Watford has taken reps at all five positions on the offensive line.

"Coach Goody is doing a great job having players rotate and getting work at all the positions, getting them ready no matter who they are," Watford said. "No matter what position you primarily were, you are going to play something other than that one position, so regardless who is here when that time comes, everyone will be ready and well-equipped."

Goodwin mentioned Boehm's work so far, as well as center Taylor Boggs. Tackle is where the Cardinals are the thinnest. Speculation the team could eventually sign a veteran there has been raised, although Watford isn't the only non-tackle trying his hand there. Former undrafted rookie guard Antoine McClain, who spent last season on the practice squad, has potential and is also getting some reps at tackle. Fifth-round draft pick Cole Toner came in with the understanding he would need to learn guard and tackle.

"The more you can do the better off you are," McClain said. "I was told before I left after the season, 'Get smarter, stay in the playbook, get stronger. Know how to play both.' "

Or all five, as Watford has done.

"You never know what's going to happen," Watford said. "I'm fortunate enough to be able to play all five now.

"It's still about fighting for a spot. The main goal hasn't changed."