Per Mertesacker
Mertesacker limped off against Reading and is a doubt for the Chelsea game Getty Images

Arsenal defender Per Mertesacker remains a doubt for the clash with Premier League leaders Chelsea as he continues to nurse an ankle problem suffered in the FA Cup win over Reading.

The German centre-back was replaced after 63 minutes at Wembley with an ankle problem, with reports suggesting he will miss the summit meeting with the Blues on 26 April.

But Wenger admits that Mertesacker is "50-50" for the game against Chelsea, and could be one of four potential absentees for Arsenal.

"Mertesacker is still in the treatment room," Wenger told a pre-match press conference. "I don't know if he's available. He is 50-50 at the moment. He has not practised at all. If Mertesacker is not ready then Gabriel will play. Oxlade-Chamberlain is out, Arteta is back in training."

Oxlade-Chamberlain has been out since March with a groin problem, while Arteta's return to training comes after five months out following ankle surgery, which followed another spell out with an ankle injury.

Hector Bellerin is also expected to miss the game with an ankle problem that forced him to miss the FA Cup semi-final against Reading after a recent run in the first team.

The game sees Cesc Fabregas return to Arsenal for the first time since joining Chelsea in the summer transfer window, a deal which came only after the North London club had turned down the chance to sign the Spanish midfielder for a second time.

Fabregas enjoyed a stellar eight years at Arsenal but his move to title rivals Chelsea could see him given a rough reception by The Emirates Stadium faithful.

"My regret is him leaving here [to Barcelona in 2011]," Wenger said of the chance to re-sign him in the summer. "I want every player to be respected."

Wenger's rivalry with Jose Mourinho is among the most documented in English football, with the Chelsea boss having labelled the Gunners manager as a "specialist in failure" last season.

But the Frenchman does not want Sunday's game to become engulfed by the off-the-field conflict between the pair and says Arsenal must find a solution to the problems that the runaway league leaders could cause.

"Sunday's match not about [the] relationship between managers," he said. "It is about watching a good game.

"Chelsea are the most consistent team. Defensively strong. We will adapt to whatever they do and find a solution to every problem we face."