Messi missed Inter's 4-1 defeat to Chicago on Wednesday as he continues to struggle with his fitness -- he has played just 37 minutes for the club since September 3.
Argentina host Paraguay on October 12 and then travel to play Peru five days later in CONMEBOL qualifiers for the 2026 World Cup.
The 36-year-old has missed Inter's last three games and five of their last six but little detail has been given about his physical condition.
Miami's Argentine coach Gerardo 'Tata' Martino initially said Messi was struggling with "muscle fatigue" but later referred to him being troubled by "scars" from an old injury.
The captain of Argentina's World Cup winning team last year in Qatar, Messi played and scored in his country's 1-0 win over Ecuador in Buenos Aires on September 7.
He asked to be substituted in the final minutes of that game and then missed the game, five days later, against Bolivia in La Paz, watching his team-mates from the sidelines.
Without Messi, Miami have failed to win their last three games, as their bid to reach the MLS playoffs has faltered.
Wednesday's game in Chicago was moved to Soldier Field, the home of the NFL's Chicago Bears and drew a crowd of 62,124 with many buying tickets in the hope of seeing the seven-times Ballon d'Or winner.
Martino was asked after the game about Messi's condition ahead of Saturday's game against Cincinnati and indicated he was improving.
"I think he's getting closer to playing again. We said, we'll evaluate him... to see if he's in condition (to play)," he said.
"The most important thing is he's leaving his injury behind and slowly discovering his best form... we'll see what's best ahead of the next game," he added.
Messi's Miami team-mate, 21-year-old winger Facundo Farías, has been called up to the national team squad for the first time.
Manchester United winger Alejandro Garnacho has also been included in Lionel Scaloni's squad for the upcoming qualifiers.