Berkman, who is hitting .269 and leads the team in homers (18), RBIs (55), walks (67), slugging percentage (.520) and on-base percentage (.402), said his leg didn't feel too great despite getting treatment on it Friday.
"It's just tight and sore," he said. "It's probably a small pulled muscle or something like that. I'm just worried about a lingering issue, which I obviously don't want, especially going into a pretty important stretch for us here in the first part of the second half."
Berkman wasn't exactly sure if he injured the calf while running to first base in the eighth inning or when he hit the base. He said it was the hardest he's run to first base this year despite being thrown out.
"I didn't necessarily feel a pop or anything like that," he said. "As I was slowing down as I hit the bag is when I really started to feel it. It's something that I guess I may have had a strain in there for a couple of weeks. I've just kind of been managing it and it flared up."
Berkman peppered head athletic trainer Nate Lucero with questions about the injury Friday and said the medical staff didn't seem too concerned. Houston general manager Ed Wade said it doesn't appear Berkman is headed for the disabled list.
"Literally, when they say day to day, that's what it is," Berkman said. "We'll see how it is every day when I come to the park."
The Astros can take comfort that Berkman's numbers against Dodgers pitcher Chad Billingsley, who started Friday, and Saturday starter Clayton Kershaw aren't great. He's 2-for-15 in his career against Billingsley and 1-for-5 against Kershaw.
Brian McTaggart is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.