"Right fielder Justin Upton could be done playing ball in 2010.

D-backs interim skipper Kirk Gibson said as much Tuesday afternoon before his club's series opener with the Colorado Rockies.

Upton, who aggravated his stiff left shoulder on Aug. 30, has started just two of the Arizona's last 19 games. He served as a ninth-inning pinch-runner and stole a base in losses on Sept. 11 and 17.

"We're going to make sure," Gibson said, "there's not going to be any further damage."

Upton worked out at Chase Field on the club's off-day Monday and also prior to Tuesday's game."