Five pounds lighter but feeling better, Broncos running back Montee Ball watched practice Saturday for the first time since undergoing an appendectomy Monday.

Ball doesn't know when he will play, but he remains pleased with his progress.

"Right now I am getting healthy and strengthening my core, just listening to my body. Just taking it day by day, step by step," Ball said. "When you see me back in pads, you will know I am ready."

Playing in the preseason remains the goal, Ball admitted. However, coach John Fox said it's not necessary if the running back needs more time to recover, planting the seed that Ball might not return until the season opener Sept. 7.

"We will play it by ear," Fox said after Saturday's morning practice at Dove Valley. "We saw him play plenty a year ago. And we saw him plenty this offseason."

Ronnie Hillman remains the starter in Ball's place, backed by rookies Juwan Thompson and Kapri Bibbs. Both received some first-team reps Saturday. The Broncos are pleased by the performance of the young backs but will continue to monitor whether to add a back. C.J. Anderson, who was competing with Hillman for the No. 2 spot, will remain sidelined until late this week based on the NFL protocol for concussions.