Arsenal's Lucas Perez out for eight weeks but Aaron Ramsey back

Arsenal forward Lucas Perez will be out for up to eight weeks with an ankle injury but Aaron Ramsey is fit to return this weekend.

Ramsey will be part of the squad for the first time since the opening weekend when Arsenal travel to Sunderland for Saturday's lunchtime game, live on Sky Sports.

But £17m summer signing Perez could be missing until Christmas after a tackle from Reading's Danzell Gravenberch during Tuesday's EFL Cup tie left him with damaged ligaments.

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Santi Cazorla, Theo Walcott and Nacho Monreal all need fitness tests on Friday ahead of the weekend, while Wenger estimated Perez's absence at "six to eight weeks".

"It's very frustrating," Wenger said at his pre-match press conference. "He worked very hard to get there, and he's absolutely gutted.

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"It's an injury that came from nowhere. A stupid one - a deliberate kick. It was similar to Granit Xhaka [sent off for a foul on Swansea's Modou Barrow this month] but no red card, though a red card would not have helped Perez.

"It was not needed, but I think it was more a frustrated reaction from the player. He had no chance to get the ball, but you have to deal with that. Sometimes you get away with it. Sometimes you get a bad injury."

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Wenger plans to be "cautious" with Ramsey, whose hamstring injury has kept him out for 13 games, while Walcott is a doubt with a minor hamstring problem and Monreal has "muscle tightness".

Xhaka remains suspended and Cazorla (Achilles) was missing during last weekend's goalless draw with Middlesbrough, but Wenger says his fit players must learn to cope without the Spaniard.

He added: "Against Boro people say Santi did not play, but I believe we had enough quality to win the game and that's where we have to find a solution even when Santi is not there - no matter how big Santi is."

Arsenal must also solve the problem of dealing with Jermain Defoe on Saturday, according to Wenger, who was impressed with the striker's decision to turn his back on MLS side Toronto last year and return for a final crack at the Premier League.

Defoe, 34, scored 15 league goals last season, and Wenger said: "You have to admire him for what he has done.

"When a guy at his age moves to the MLS you think that's the end in the Premier League, but he came back and had a huge impact and it's down to him that Sunderland stayed in the league.

"There must be a big passion there. I don't know him well, but he is absolutely amazing."