But Argentina manager Gerardo Martino was coy on Monday as to whether Messi will be on the field from the start, or if it'll be another supporting performance off the bench from the star forward who has been dealing with a back injury.
Argentina is already assured of a place in the quarterfinals of the tournament and is likely to be the top of Group D baring the highly unlikely scenario of a Bolivia win and a barrage of goals scored by Chile against Panama.
He certainly looked healthy in his limited role last Friday against Panama. Messi played just 29 minutes and managed to score a hat trick in the 5-0 victory that clinched Argentina's passage to the next round of the tournament.
"He could have started if it was necessary," Martino said through an interpreter. "After four days, as I understand he's even better."
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There is concern for Argentina headed into a game with little to play for. They are likely to be without Angel Di Maria because of an adductor injury suffered in the victory over Panama. There is the lingering wonder if Messi's back injury could get worse.
Martino said there was no timeframe on when Di Maria -- who scored in the opening win over Chile -- may be able to return from his injury.
"I know after 48 hours of his injury he was not able to (run) around the field," Martino said. "He is a little bit happier. ... We have this expectation and hope that he will heal fast."
And there are the expectations that are now even heavier on the Argentinians with the surprising early exits of Brazil and Uruguay.
Messi has not won any major senior trophy since joining the national team in 2005 and Argentina's last major title other than the Olympics was the 1993 Copa America.
Martino was asked repeatedly on Monday about Brazil's surprising exit in Sunday's loss to Peru on a controversial goal.
"I did watch the play that score and the hand, and then really to be able to make a comment or analyze the Brazil team I should not be doing it," Martino said.