Injured Arsenal midfielder Aaron Ramsey will be out for another three weeks, Arsene Wenger has revealed.
Ramsey's return from the hamstring injury he suffered on the opening day of the season against Liverpool has been gradually pushed back by Arsenal, with the Welshman originally expected back after the international break at the start of the month.
But Wenger said on Friday that he'll now be out until Arsenal's home game against Swansea on Oct. 15, which follows the next international break for World Cup qualifying.
"Aaron Ramsey is still struggling with his hamstring," Wenger said at his prematch news conference ahead of Saturday's Premier League meeting with Chelsea. "I don't think he will be available for our next game against Basel or at Burnley. So before the [next] break, he will not be available.
"He has a small Grade 1 hamstring [tear]. But he's not completely free in his mind yet to push completely. We stop him every time when he has a little pain. He's in the last, last days of his rehab. As long has he's not completely comfortable we don't push him."
When asked if he was worried about the Welshman, who has a history of hamstring problems, Wenger said: "Not really because it's nothing major. But I'm a bit more cautious than I would be [if he had not had previous problems]. If he was ready to play I would involve him in the squad of course, but he is not."
Olivier Giroud, meanwhile, could be back against Chelsea after missing the last two games with a toe injury but has yet to prove his fitness.
"Giroud has a test today to see if he can be involved. He had a good training session yesterday," Wenger said. "I thought he'd be short for tomorrow but we'll see how he comes out of today's training session."
Giroud has yet to start a game this season for Arsenal, and Wenger also has the option of playing Alexis Sanchez or new signing Lucas Perez -- who scored twice against Nottingham Forest in the EFL Cup on Tuesday -- up front.
Regardless of who his striker is, Wenger said the key against Chelsea will be to stay disciplined and avoid another early sending off. Arsenal had a player sent off in the first half in both games against the Blues last season, and also in the 6-0 drubbing at Stamford Bridge two years ago.
"We have talked about that because in the last two games we played against Chelsea with 10 men," Wenger said. "So of course for the result tomorrow it will be important how we play football, but also the way we behave.
"Discipline and results are strongly linked and the regrets we had in the last two games is that we couldn't play with 11 against 11."
The key to that will probably be whether they can cope with Diego Costa. The Chelsea striker clashed with Gabriel Paulista, which led to the Arsenal defender being sent off at Stamford Bridge 12 months ago, and then forced Per Mertesacker to make a late tackle that earned a red card at the Emirates in the return game.
"By being completely cold blooded and just focusing on your game and not responding," Wenger said of how his players should deal with Costa. "Just try to [neutralise] his qualities and his game.
"You need to be committed but by respecting the rules of the game and not responding. I believe last year we were a bit unlucky at Chelsea to be down to 10 men, because he [Costa] was suspended after [being charged with violent conduct].
"In the second game we deserved the red card [Per Mertesacker for bringing down Costa], because we were caught on a quality run from him."