SANTA CLARA, Calif. — Once again seeking to lead Argentina to their first international title since 1993, Lionel Messi has hardly enjoyed what anyone could describe as the ideal preparation for the Copa America Centenario.

Just five days after helping Barcelona clinch a league and cup double with victory in the Copa del Rey final, the five-time Ballon d’Or winner was back in his home country featuring in his side’s one and only warmup match for the tournament in the United States. Yet before the match had even been completed, Messi had been taken to a nearby hospital for a scan on a back injury. The good news arrived that there was no fracture, but Messi’s pre-tournament ordeal had only just begun.

Soon he was on a flight back to Spain, appearing at his trial for alleged tax fraud. The proceedings complete, but a verdict still to be announced, only on Friday was Messi back with his Argentina teammates ahead of their Copa America opener against Chile at Levi’s Stadium in Santa Clara, California, on Monday.

His participation in that match remained unclear on Sunday, however. After the 28-year-old trained separately from the rest of the group on Saturday, coach Gerardo Martino revealed that Messi’s fitness would be assessed in the team’s final training session on Sunday evening.

“The first thing that we do is listen to the doctor, who is the most important voice in this matter,” he said. “After that we need to hear Leo, he’s the second most important voice. I will give him my point of view when it comes to it.”

If Messi fails to make the starting lineup, Martino confirmed that Benfica’s gifted playmaker Nicolas Gaitan would be his replacement. Still, there is no doubt that Messi’s absence would be a signifiant blow both for the player and his team.

While some of their South American rivals have prioritized the upcoming Olympics or the ongoing World Cup qualifiers, for Argentina the Copa America Centenario represents a precious chance for some long-awaited silverware. The drought now extends to 22 years after agonizing near-misses in the past two summers.

First, in the final of the 2014 World Cup came an extra-time defeat to Germany. Then 12 months later it was a loss on penalties in the Copa America final to hosts Chile. Messi was a part of both those teams and, a consequence of his status as the world’s greatest player, took more criticism than any other for Argentina’s failures.

A rematch with Chile to kickoff their latest bid for glory provides an ideal chance for Argentina and Messi to suggest that this tournament will have a far happier ending.

Chile will be in no mind to relinquish their first ever international title after just 12 months, yet much has changed since the explosion of joy that accompanied their triumph in Santiago. The mastermind of the success, coach Jorge Sampaoli, departed in January and the team has yet to show the same form under Argentine-born replacement Juan Antonio Pizzi.

Indeed it is now three defeats in Pizzi’s four games in charge, after Chile lost both their warmup games, to Jamaica and Mexico. Chile should, though, be back to full strength for Monday’s opener, after Messi’s Barcelona teammate Claudio Bravo joined up with the squad.

Prediction: Chile have not yet looked the same irresistible force under Pizzi and also have Arturo Vidal and Alexis Sanchez appearing jaded after long seasons in Europe. Pizzi’s reign kicked off with a home defeat to Argentina, and, even if Messi is unavailable from the start, Martino has the attacking options to get his side off to a winning start.

Predicted score: Argentina 1-0 Chile

Kickoff time: 10 p.m. EDT

TV channel: Fox Sports 1, UniMás, Univision Deportes

Live stream: Fox Soccer 2Go, Fox Sports Go,