"It's pretty much the same," Berkman said from the clubhouse during Saturday's game. "I hope to make an improvement, but it hasn't yet.
"It's hard to say [a return date]. I can bend it, but it's just a matter of bearing weight on it. And once you get to that point, you're still three to four days away from where you can do much."
The Astros placed the five-time All-Star on the disabled list retroactive to March 26 after Berkman's left knee swelled during an attempted workout on Tuesday. He will be eligible to come off the disabled list on April 10 against Philadelphia -- Houston's fifth regular-season game.
Berkman had arthroscopic surgery on the knee on March 13 to clean out loose cartilage, and the Astros said the timetable for his return would be two to four weeks. April 10 would be four weeks from the procedure.
"It's a slow process," Berkman said. "It's frustrating. Everyone wants an answer and I don't have one.
"I've had it drained four times, and I think we're going to do it a fifth time to try and get the swelling out of there. That's the biggest battle right now."
Veteran infielder Geoff Blum will start in Berkman's place at first base in the Astros' home opener on Monday against the San Francisco Giants.