Argentina face Peru without Messi and Scaloni in final Copa América group clash
The eight-times Ballon d'Or winner sustained a thigh injury in Argentina's 1-0 win over Chile.
While he did not participate in Thursday's training, reports suggest he could be fit for Argentina's quarter-final fixture on July 4.
"We will go day-to-day awaiting his evaluation. We also had a matter of overload so in order to avoid questions on that topic, we won't have him for the next match," assistant coach Walter Samuel told reporters on Friday through a translator.
Samuel stood in for head coach Lionel Scaloni at Friday's press conference, as Scaloni is suspended for the Peru match due to Argentina's tardiness after halftime in their two previous matches.
Messi's absence may disappoint fans in Miami, as another sellout was expected.
However, with Argentina already securing a spot in the quarter-finals and looking likely to top the group, precautions are being taken for the Inter Miami star.
Argentina could only lose the top spot to Canada if they suffer a defeat against Peru and Canada clinch a significant victory over Chile.
Argentina are expected to rest several other key players for the Peru match, possibly introducing talents Alejandro Garnacho (Manchester United) and Valentin Carboni (Inter Milan) to the field.
"We are not underestimating our opponent," Samuel said. "We are always playing to win."
Peru, on the other hand, need to secure a win against Argentina and hope for Canada to lose to Chile to keep their chances of qualification alive.
Peru's campaign so far has seen them draw 0-0 against Chile and lose 1-0 to Canada, the latter after Miguel Araujo received a red card.
Despite the results, Peru coach Jorge Fossati remains upbeat.
"In the first half, we challenged Canada more than Argentina challenged them and I am talking about Argentina, the current world champions," he said.