TUCSON, Ariz. — Arizona outfielder Eric Byrnes, returning from hamstring injuries, is being held out of spring training games because he can't run full speed on the base paths.

Diamondbacks manager Bob Melvin said he hopes Byrnes will be able to play in mid-March.

"The one thing he hasn't conquered yet is making the turn at second (base) when he's going from first to third," Melvin said before the Diamondbacks played Oakland on Sunday.

Melvin was optimistic that Byrnes will be ready for the season opener April 6.

"If he starts playing games (in mid-March), he's not questionable at all," Melvin said.

Byrnes, in the second year of a three-year, $30 million contract, came to camp hoping to contend for a spot in the Diamondbacks' crowded outfield. Conor Jackson took over in left field last season, when Byrnes went on the disabled list for the first time in his career.

Byrnes played in only 52 games, batting .209 with six homers and 23 RBIs. He is a career .263 hitter with 101 homers in nine seasons.

Byrnes said he didn't feel as if he'd had a setback. He's wary of pushing too hard, too soon.

"I've been able to run," Byrnes said. "I'm just not able to run at full speed on the bases right now."

Byrnes said he has been taking extra batting practice at the Diamondbacks' minor league camp, and he is optimistic he'll be on the opening-day roster. He said a limited slate of spring training games would be enough to prepare him for the regular season.

"My goal is just to be able to break camp with the team," Byrnes said. "I think I'll still be able to get in there in time to do that. Not to mention the fact that I'm doing everything else, including taking at-bats over at the minor league complex.

"I think as long as I come back able to play full speed is the most important thing," he added.