Jose Mourinho has defended Radamel Falcao's low-key start to his Chelsea career and re-iterated that he is unsure whether fellow striker Diego Costa will be fit to face Swansea City on Saturday.

Chelsea boss Mourinho lured Falcao to Stamford Bridge on loan from Monaco, despite a poor return of just four Premier League goals during an unhappy spell with Manchester United last season.

Falcao made little impact after coming off the bench in Sunday's 1-0 loss to Arsenal in the Community Shield and was again ineffective in Wednesday's 1-0 defeat to Fiorentina in the International Champions Cup.

With Costa struggling with a hamstring problem, Falcao may be selected to lead the line when Chelsea start its defense of the Premier League title against Swansea, and Mourinho is happy with the Colombian's progress following his late return to preseason due to his participation at the Copa America.

"He [Falcao] is very good, he's very good for the situation," Mourinho said. "He played at the Americas Cup [Copa America], then had his holidays, he has had one week of training sessions, not the three weeks the others have had.

"He has had minutes in the different matches. I took him off in his best moment when he was in his best moment in the game. I'm happy with his evolution, very happy to be fair."

On Costa, Mourinho added: "I don't know whether he will be fit to play on Saturday. I don't risk to say yes, I also don't risk to say no. I don't know is the truth. Friday is the day before the game, I will tell you probably I don't know. It was a surprise for me that he couldn't play at the weekend."

Mourinho also stated that Eden Hazard was limping but allayed any injury fears and confirmed Victor Moses is fine despite taking a knock during the Fiorentina match.