Chelsea striker Fernando Torres has suffered a medial collateral ligament injury to his left knee and will be out of action for approximately three weeks, the Premier League club have confirmed.
The 29-year-old underwent a scan at Chelsea's Cobham training base after limping out of Tuesday's Champions League group game at Steaua Bucharest and the extent of the damage has now been revealed.
A statement published on Chelsea's official website read: "Chelsea Football Club can confirm Fernando Torres suffered a medial collateral ligament injury to his left knee in the Champions League group game at Steaua Bucharest on Tuesday evening.
"The 29-year-old will be out for approximately three weeks."
Blues manager Jose Mourinho had expressed his hope after the 4-0 win in Romania that Torres would be fit for the Premier League contest with Cardiff on 19 October.
Just a few hours after learning he would face no further Football Association disciplinary action following his altercation with Tottenham defender Jan Vertonghen, the Spain international hobbled off after 11 minutes of action at the National Arena.
And Mourinho had on Tuesday night been able to confirm Torres would not be available to link up with Spain for World Cup qualifiers against Belarus and Georgia following Sunday's match at Norwich, for which he was suspended irrespective of injury following his dismissal at White Hart Lane.
"It's something in his knee, his ligament, and we have to wait for the scan," Mourinho said.
"The doctor is very confident it's not a big injury, like we had with Marco van Ginkel (who is out for six months).
"He knows that he doesn't play against Norwich. He knows that he cannot go to the national team.
"He knows he has 15 days until the next match he can play, which is against Cardiff.
"Let's see the scan. If the injury is an injury for 15 days, I think he'll be fine. That's okay.
"The problem is if it's more time and it's a pity for the guy, because he's in a very good moment."