The Liverpool striker limped off after only 17 minutes of the game, giving Rafael Benitez more injury worries.
"I knew I had to go off straight away," said Baros. "I could feel it as it is the second time I've felt the muscle. I knew immediately what was wrong as it has happened before."
With Djibril Cisse already out with a broken leg, Benitez will now block Neil Mellor's proposed loan move to Sheffield United and rely on youth to see the club through until the transfer window reopens.