Berkman, the team's leader in home runs and RBIs, suffered the injury running the bases Thursday in Los Angeles and was out of the starting lineup the next three games. He played in Monday's series opener against St. Louis, but he was noticeably favoring the leg.
"I'm glad it's not torn, which is what I was concerned about," said Berkman, who is available to pinch-hit. "I'm not a medical man, but it sounds like it was almost that way. It's not great, but it's not terrible either."
Berkman and general manager Ed Wade said the five-time All-Star would have likely tried to play through the injury if it were later in the season. Still, not being in the lineup for the final two games of the Cardinals series is tough for Berkman to take.
The Astros, who have an off-day Thursday, began play Tuesday three games behind St. Louis in the National League Central.
"If this were the playoffs or World Series -- and given our opponent and standing, it feels like a playoff-type game -- I would certainly be in there, but as Ed and I were talking, it's July and not late August or September," Berkman said. "There's no reason to push it. If it comes back up later in the season you might play through it, but right now the smart thing is get it calmed down for a couple of days."
Astros manager Cecil Cooper declined a request to talk to the media following Berkman's diagnosis, but Wade filled in reporters.
"If this was late September, then it might be a situation you say let's go ahead and try to gut through this thing, and the reality is this is July and there's a possibility he could aggravate it and be out for an extended period of time," Wade said. "If your choice is to take a couple of more days and let it get back to 100 percent, that's the appropriate thing to do."
Berkman, who will have to wear a protective boot, limped into second base on a first-inning double Monday. He went 1-for-2 with a walk, but admitted he was limited in what he could do. The Astros tried to talk him out of the game in the first inning, but Berkman wound up playing all nine innings.
"The whole time my mind-set was kind of, 'Go easy,'" Berkman said. "I knew that was a for sure double, but as I was rounding first, it didn't feel great. I dragged the old limp leg into second base. The problem I have with going out there now is, let's say there's a ball down the line I know I can get to, I'm going to try to get to it.
"I don't want to be out there if I'm not covering the ground defensively or if I'm not able to advance a base when they should be able to get somebody else in there who we know can move better."
Wade said the injury isn't as severe as the Grade 4 calf strain suffered by closer Jose Valverde earlier this year. Valverde, who missed 41 games, also had a hematoma that had to be aspirated in addition to the muscle strain.
Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.