"That's when I did it, which sounds a little ridiculous," Berkman said. "I find it quite unbelievable myself. It's just when you're in desperation mode, trying to score from first."
Berkman left batting practice early Saturday to receive treatment for the spasm and said in retrospect he should have taken himself out of the game after his first at-bat.
"I can't turn my neck," he said. "I had to hit completely different than I normally would."
Berkman played defense in the bottom of the third, but while the Astros were batting in the next frame, he was officially removed from the game. Darin Erstad took over at first base and logged two hits, drove in a run and scored twice.
"Darin's a good hitter, which he proved by getting a couple of hits," Berkman said. "I'm hurting us by hitting in that spot. Get somebody in there that can swing the bat."
If he doesn't improve overnight, it's likely he'll sit for Sunday's game.
"I never want to rule anything out," Berkman said. "I don't want to take myself out of the lineup before I show up and see how it feels. If it feels like it did today, I'm just not going to be able to do it. It's not a question of want to. It's just physically, if you can't turn your head, you can't do it."
The Astros were dealt another blow in the seventh when Ty Wigginton left the game with a bruised left thumb. Digital X-rays taken later that day showed a small fracture in the thumb. Wigginton will be re-evaluated by Dr. Tom Mehlhoff on Monday.
Wigginton presumably suffered the injury when Jason Marquis was thrown out at third trying to advance on Alfonso Soriano's fly ball to center.
Wigginton had a rough day defensively at third before he left with his injury. He fielded a routine grounder from Marquis in the fifth, but threw the ball over Erstad's head, allowing Marquis to reach second. Wigginton also made several off-line throws to first throughout the game, but was saved by slick fielding efforts from Berkman and Erstad.
Wigginton was replaced by Mark Loretta, who had started the game at second base. Tomas Perez took over at second.