Despite their struggles in MLS, Inter Miami has clinched the Leagues Cup with Messi in their ranks and has also reached the final of the US Open Cup.
However, there is now significant doubt about the 36-year-old's availability for next week's crucial match against Houston Dynamo, as he was forced to leave the field during the first half of the Toronto match.
Messi, the former Barcelona and Paris Saint-Germain star, was making only his third appearance in the league before his departure in the 37th minute. His exit came just two minutes after Jordi Alba was also substituted due to fitness concerns. Nevertheless, Inter Miami managed to secure a 4-0 victory over the Eastern Conference's last-placed team.
Following the match, head coach Gerardo Martino addressed the situation, ruling Messi out of the next MLS game on the weekend and suggesting that he faces a race against time to recover for the crucial clash with Houston. Martino stated to reporters, as quoted by BBC Sport:
"There is no chance they will be there on Sunday.
"I know we have a final to play [on Wednesday] but they won't go near the pitch if they can't play."
Messi had missed Argentina's second fixture of the international break and the 5-2 defeat to Atlanta United last weekend before being brought back into the team.
Martino added: "The scans [Messi] had with the national team, they didn't show any injury. We still saved him to be safe.
"We don't think he has a muscular injury. That's also from a conversation I just had with him. But we have to continue being careful. We'll look at it the next few days."