The centre-back has not played a game since January, having been forced to endure a spell on the sidelines with injury.
However, the 26-year-old has reported to international duty and could feature for his country against Macedonia.
"Vincent is now training with the physical coach," assistant coach Vital Borkelmans told Sky Sports News. "He also trained very hard at City.
"He is very important for the group and we are quite happy he is here. We will make a decision on Wednesday or Thursday whether he can play or not.
"We talk many times with the coach [at City] but Vincent is very important to us. He is the captain of the team."
The news is likely to upset Mancini, who appeared to anticipate Kompany missing the international fixtures in order to fully recover.