LONDON -- Arsene Wenger has admitted Arsenal must analyse their injury crisis "very deeply," and says it is a "concern" for the Premier League title-chasers.
While insisting that many player absences are down to "bad luck", the Emirates boss revealed that the coaching staff noticed Mesut Ozil was struggling early on against Bayern Munich with a hamstring injury before being replaced at half-time -- with the midfielder confirming he sustained the injury in the second minute.
The Germany international is likely out for four weeks, according to Wenger, and is one of a number of key players missing from this Sunday’s derby against Tottenham including Jack Wilshere, Theo Walcott and Aaron Ramsey.
The sheer number of injuries has led outspoken Dutch physiotherapist Raymond Verheijen to question that there is a "problem" with the way Arsenal train "in general, but especially in preseason" -- and Wenger acknowledged something may have to change.
"I am concerned that that happens," he told a news conference on Friday. "If you look at our overall injury list going into such a final decisive part of the season, we have no Wilshere, Walcott, Ozil, Ramsey.
"We went to Bayern with no [Kieran] Gibbs or [Nacho] Monreal. Of course it is a concern. We are analysing very deeply why it happened to see if there is a link between these injuries.
"Walcott, it is completely bad luck. Wilshere I don't think it is linked with the other injuries, it is linked more with his history and the kick he got. The rest maybe we have to find out why it happened."
Monreal is "definitely available" this Sunday, but Wenger says he is unsure over Gibbs’ fitness, while Ozil’s injury is a pressing issue.
"We lose of course Ozil who has been injured on Tuesday night, and I don't know for how long exactly he will be out -- but it looks a minimum of three weeks," Wenger continued.
"When the minimum is three weeks, the maximum is six. Honestly I am not specialist enough to know. It's a grade two hamstring, let's say four weeks."
Wenger also dismissed some of the criticisms Ozil faced after the 1-1 draw in Munich.
"He had a very good game against Everton on Saturday and I feel he was handicapped from early on in the game [against Bayern] by this hamstring because I saw him stretching a few times,” he said.
"I told my physio 'Is he alright because he looks to stretch his hamstring?' It looks to me that he played a long period in that first half being injured."
The injury leaves Wenger somewhat short of creativity, but he revealed Kim Kallstrom is in the squad for the first time since joining in January.
"It is of course a blow but I am confident we have the quality without [Ozil] during that period," he continued. "We have many creative players in our squad who can take over and produce quality performances.
"I am convinced that the team is ready, even without Ozil, to go for the challenge."
The one other concern Wenger expressed was regarding the slow pace of Ramsey's anticipated return. The midfielder has been out since Dec. 26 with a thigh injury after a fine start to the season.
"That's our worry at the moment, [that] Ramsey takes longer than expected. He had a first setback and now it's slower," he added.
"It was the plan for him to join in on Thursday but he still has recurrent pains in his thigh and of course he's now a little bit apprehensive because of the setback he had.
"We have to be very cautious with him -- when will he be back? I believe it's two more weeks now."