A Q-tip couldn't push Montee Ball further inside Peyton Manning's head.

Ball perches atop the Broncos' depth chart at tailback — "Everyone else is competing for second," said offensive coordinator Adam Gase — and remaining there depends on understanding Manning's symphony at the line of scrimmage.

"Playing with No. 18 back there, he is capable of making any check at anytime with two seconds on the play clock," Ball said. "You have to be able to comprehend it and react to it. I am really studying the playbook, and watching film and making my own checks to see what he might do."

Thinking along with Manning carries the risk of frustration. Paint with Van Gogh, and it's not easy to connect the dots without blotching colors. As a rookie last year, Ball realized in training camp that he could handle the physical nature of the NFL. The mental challenge jarred him, though, and the light bulb did not stop flickering until Week 12 of the season. He began anticipating Manning's audibles, a necessary skill to not only exploit off-balance defensive fronts but pick up blitzes.

"I started playing better then," said Ball, knowing that allowing free shots on Manning is a free pass to the Denver bench. "I wish that it had happened earlier. I always tell myself, imagine what it would have been like had I begun like this."

Ball, 23, lost three fumbles last season — but only one after Week 3. He scored four times over his final nine regular-season games, and posted a career-best 117 yards rushing against the Chiefs on Dec. 1. The glimpses of production explain why the Broncos have faith in Ball and didn't pursue a veteran replacement for Knowshon Moreno, who signed with the Dolphins as a free agent.