Messi, who is one goal shy of Gerd Muller's 1972 record of 85 in a calendar year, suffered a major injury scare in the closing stages of Wednesday's goalless final Champions League group game against Benfica at the Nou Camp.
"If Messi travels it's because he's ready to play," coach Tito Vilanova said today at his pre-match press conference. "If there was the slightest risk, he wouldn't be going.
"He completed training on Saturday without any kind of trouble. There are still a lot of hours until kick-off and we'll all evaluate the situation together and decide whether he'll play the full 90 minutes or just part of the match.
"The important thing is that he's feeling okay. But he could easily wake up in the morning and tell us he's feeling pain again."