KISSIMMEE, Fla. -- Hunter Pence, the Astros' Most Valuable Player a year ago, and newcomer Clint Barmes were among more than a dozen non-catching position players who were working out at Osceola County Stadium on Wednesday. The full squad isn't required to be uniform until Sunday.

The hitters took cuts in batting cages, worked out on their own and took batting practice on one of the back fields while pitchers and catchers finished up their workouts. Among the other Major Leaguers to report early were Chris Johnson, Brett Wallace and Tommy Manzella.

Koby Clemens, J.D. Martinez, T.J. Steele, Jack Shuck, Brian Dopirak and Drew Locke -- all in Major League camp for the first time -- were also among the other position players in camp a few days early.

"It's great seeing these guys want to come out and get their work in," Astros manager Brad Mills said. "They're thrilled to be on the field. It's a treat to get to go down and talk to them in this atmosphere as well."

Early in camp, Astros in good health

KISSIMMEE, Fla. -- The Astros made it through their first day of workouts without any new injury concerns. General manager Ed Wade said on Wednesday that the only pitcher not on the program is right-hander Sammy Gervacio, who had shoulder surgery last month after missing most of 2010 with arm problems.

Infielder Jeff Keppinger, who had foot surgery in January to correct a problem that plagued him toward the end of last year, was in camp on Wednesday, wearing a walking boot. Wade said that the boot should be off soon, but Keppinger isn't expected to be ready until May at the earliest.

Right-hander Alberto Arias, who missed all of last year after undergoing extensive right shoulder surgery in April, reported to camp healthy and is on the regular throwing program. Jeff Fulchino, who had surgery to remove inflamed tissue and a bone spur from his right elbow in October, was also good to go.

The only person slowed by health other than Keppinger and Gervacio was manager Brad Mills, who had right knee replacement in October. Mills participated in drills and roamed the fields for much of Wednesday's workout.

"Everything was OK until I started standing around and watching BP, and I had to go sit down," Mills said.

Astros single-game tickets on sale Friday

KISSIMMEE, Fla. -- The Astros announced that single-game tickets for upcoming regular-season games at Minute Maid Park will go on sale to the general public at 9 a.m. CT on Friday. Tickets can be purchased online at www.astros.com, at the Astros' Spanish website -- www.astrosdehouston.com -- at the ballpark box office on Texas Avenue or by phone, toll free, at 1 (877) 9ASTROS (1-877-927-8767).

Ticketmaster retail centers in all Fiesta and select Macy's, H-E-B, F.Y.E., Wherehouse Music and Ritmo Latino stores will sell Astros tickets during store hours. The individual ticket purchase limit for all games is 19. The complete 2011 Astros schedule can be found on www.astros.com.

As a special offer, all registered users of www.astros.com had the opportunity to purchase individual game tickets online starting on Wednesday morning.

To guarantee a seat for Opening Day prior to Friday, fans can purchase a full-season ticket package or the Opening Day 14-Game Flex Plan, which includes tickets to the home opener and home finale, as well as 12 games of the purchaser's choosing, plus an additional bonus game for free. For more information about Astros full-season ticket packages (82 games) and mini-plans, log on to www.astros.com or call the Astros' ticket services department at (713) 259-8500 or 1-800-ASTROS2.

Worth noting

The Astros signed three players on Wednesday -- catcher Jason Castro ($421,500), pitcher Bud Norris ($437,500) and pitcher Jorge Deleon ($414,000).