Cardinals first baseman Lance Berkman was on the field running before batting practice Monday night at Busch Stadium, and he has been doing some hitting drills.

Having undergone right knee surgery in late May, he is hoping to be playing for the Cardinals when the second half of the season begins July 13 in Cincinnati.

"It wouldn't shock me," Berkman said.

"I'm not banking on it, but at the same time I wouldn't rule it out.

His rehabilitation program is a simple one, Berkman said.

"If it hurts, don't do it," he said. "If it starts to swell, don't do it."