Arsenal boss Arsene Wenger admits Cesc Fabregas is struggling to be fit for their clash with Chelsea next week.

Wenger has ruled Fabregas out of this Sunday's trip to Middlesbrough, together with Alexander Hleb and Mathieu Flamini, and suggested that he may struggle for the game against Chelsea.

"We have no one coming back for Sunday [at Middlesbrough]," said Wenger. "And to put a date on that is very difficult. If you ask me who will be the first to come back, then I think it could be Mathieu Flamini. Cesc and Alexander Hleb are on the same line but whether they come back next week or in two weeks I don't know."

Fabregas pulled his hamstring in the Champions League defeat against Sevilla last week and, although the team won well at Aston Villa on Saturday in his absence and secured a battling point at Newcastle United on Wednesday night, Wenger believes that they cannot win the Premier League without him.

"What's true in one game is not over 10," the Frenchman said after the 2-1 win at Villa Park. "In a one-off, of course you can do well. But we want Cesc with us. He's a big player. He is world-class."