Argentina captain Lionel Messi missed training on Thursday afternoon due to muscle pain, while his presence in their final Copa America group-stage game against Peru remains in doubt.
Defending champions Argentina trained at the Miami International University sports ground without Messi, who underwent medical tests and kinesiology sessions, according to Argentine media reports.
Messi, who turned 37 this week and has been suffering muscle niggles, required brief medical treatment on his thigh during Argentina's 1-0 victory over Chile on Monday at the U.S.-hosted tournament.
The Inter Miami player said it might be wiser to sit out the Peru game on Saturday with his team already qualified for the next round after two wins.
"My adductor got a bit stiff and I couldn't stay loose, it was bothering me a little bit, but I was able to finish the game, so I'll see how it evolves over the next few days," Messi said after Monday's win.
The Argentine Football Association did not give a medical update on the forward's fitness. Defender Marcos Acuna also suffered a muscle injury during training in Miami.
Coach Lionel Scaloni said he will rest his first-choice players on Saturday in the final match of Group A at the Hard Rock Stadium.