Arsene Wenger has revealed that Aaron Ramsey’s comeback from a thigh injury has again suffered a setback, ruling him out of Sunday’s clash with local rivals Tottenham.

Ramsey has been out since picking up the problem in the Boxing Day win over West Ham. After returning to training in January, he suffered a reoccurrence of the injury and was faced with another six weeks on the sidelines. While Wenger suggested that the latest issue was less serious, his comeback has again been delayed.

“We have had to defer his comeback to full training a little so he is not available,” he said, according to Arsenal’s official website. “He is having difficulties in the final stages of his rehab. It looks to be short-term.”

In the early weeks of the season, it was Ramsey and Mesut Ozil who were the inspirations behind Arsenal’s fantastic start. Now, as the club continues a crucial run of fixtures, Ozil will be missing, too. The club’s record signing suffered a hamstring injury and was withdrawn at half-time as Arsenal crashed out of the Champions League at Bayern Munich on Tuesday.

“He is out,” Wenger confirmed in his press conference on Thursday. “I don’t know for how long but it is a hamstring injury. There are scans going on.”

It is in midfield where Arsenal’s problems are particularly stark. Jack Wilshere was ruled out for six weeks after suffering a hairline fracture in his left foot during England’s friendly win over Denmark last week. There is some good news, however, with January signing Kim Kallstrom having returned to training.

The experienced Sweden international was targeted in January to provide cover for the injured Ramsey, before it was discovered that he had a back injury that would keep him out for six weeks. Still, Arsenal proceeded to sign him on loan from Spartak Moscow until the end of the season. And that capture could now come in handy, given Arsenal’s continued injury issues. Wenger explained that Kallstrom and young striker Yaya Sanogo are in the frame for Sunday, with a decision to be made on whether the 31-year-old will be able to make his debut.

“Kallstrom joins the normal training group today and Sanogo too,” he said. “I will have to decide if Kallstrom is OK to be in the squad on Sunday. I will see how he looks, it is not impossible.”

Arsenal’s other major issue has been at left-back. In the 1-1 draw with Bayern Munich, Wenger was forced to play captain Thomas Vermaelen out of position on the left of the defense, with both Kieran Gibbs and Nacho Monreal unavailable due to injury. But at least one of them is set to return in time for the north London derby.

“Kieran Gibbs has a test tomorrow but I am hopeful that Nacho Monreal will be fit,” Wenger explained. “They both have a good chance.”

After facing Tottenham, Arsenal take on Premier League title rivals Chelsea and Manchester City, either side of a meeting with Swansea City. A clash with Everton then follows, before their FA Cup semifinal at Wembley against Wigan Athletic.

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