Lionel Messi trained with Argentina on Tuesday morning during a practice closed to the media in Buenos Aires, and Albiceleste coach Edgardo Bauza said he was hopeful the Barcelona star would be fit to face Uruguay on Sept. 2.
The 29-year-old underwent tests at Barca's training ground on Monday after he ended Sunday's 1-0 La Liga win against Athletic Bilbao in discomfort.
The club confirmed that he has a sore left hamstring, but gave Messi the green light to travel to Argentina to link up with the Albiceleste.
Argentina, currently third in the CONMEBOL qualification group, host Uruguay on Sept. 2 before facing Venezuela away on Sept. 7.
Messi is to make his much-anticipated return for these matches after a brief international retirement following the loss in the Copa America final.
Messi participated in light drills during team training and Bauza was optimistic about his star forward's fitness.
"He's OK, he's OK. We are going to take good care of him," Bauza told Argentina daily Ole. "But I have faith that he will be OK for the match against Uruguay."
The Argentina FA (AFA) posted training photos via social media, but have not issued any official declaration about Messi's fitness yet.
On Monday, AFA announced that Sergio Aguero and Javier Pastore were both injured and will not play in either qualifier.
Messi, 29, called it quits on his national team after missing a penalty in the shootout defeat to Chile in this summer's Copa America Centenario final -- the third consecutive loss for Argentina in a major final.
However, Bauza, who will be coaching Argentina for the first time, had persuaded Messi to return to the squad in time for the September qualifying.
After six matches in South American qualifying, Messi and his teammates sit third in the standings behind leaders Uruguay and Ecuador.
The top four teams will qualify automatically for the World Cup in Russia in 2018, while the fifth placed team will go into a playoff match.