The Cardinals believe first baseman Lance Berkman might play this weekend against the Houston Astros. It just won't be today.

Berkman has yet to sprint since landing on the disabled list April 19 because of a strained left calf. He performed some lunging exercises before Thursday's 6-3 loss to the Pittsburgh Pirates and hopes to do more than jog in the Minute Maid Park outfield before to tonight's series opener in his hometown.

"It's pretty much day to day at this point," Berkman said. "I don't know about (today) being the day but I feel like I'm close."

Berkman, who has been limited to 23 at-bats in seven games played, has taken daily batting practice. However, manager Mike Matheny acknowledged Wednesday that Allen Craig's availability diminishes the urgency to rush Berkman back into the lineup. Craig has played two of the last three games at the position with Matt Carpenter handling Wednesday's assignment.

Matheny hinted earlier this week that Craig is not currently considered an outfield option. During his minor-league rehab assignment Craig appeared only at first base at Class AAA Memphis. Jarred by renewed swelling in Craig's knee after he made 10 plate appearances during a late-March exhibition, the club prefers to divide Craig's playing time and confine his defense to first base.

An approaching roster move to create space for Berkman will be an interesting one.

The club must weigh optioning outfielder Shane Robinson, who can play center field, vs. sending out a corner infielder such as Matt Carpenter, who is hitting .279 with nine extra-base hits and 14 RBIs.