The 21-year-old limped off during La Roja’s UEFA Nations League semi-final win over Italy, having scored twice in the first half.
Torres was subsequently passed fit to start against France in Sunday’s final, though he was forced off late on in the 2-1 defeat.
Now, City have announced that their player has picked up a “small fracture” on his right foot.
“He has since returned to Manchester for tests and will continue to be monitored,” added the club statement.
According to BBC Sport, Torres is set to miss four to six weeks of action.
In the next six weeks, City face Manchester United at Old Trafford in the Premier League and host Paris Saint-Germain in the Champions League.
Torres gone the same way as KDB. Obviously injured but played the next game causing more complications. International duty is an absolute joke. Yeah, players want to represent their country but not to the detriment of the club that pays them ffs. Rehab at City’s expense #mcfc
Torres joined City last summer in a reported £21million move from Valencia has enjoyed a superb maiden season at the Etihad.
He registered 13 goals and three assists from 36 games in all competitions, while this season, he has seven appearances and three goals under his belt.
City return to Premier League action on Saturday when they host Burnley in a 3pm kickoff.