Arsenal face a defensive crisis ahead of Saturday's FA Cup final against Chelsea with Gabriel Paulista definitely missing out through injury.
The Brazil defender was injured in Arsenal's 3-1 win over Everton on Sunday, a game that also cost the Gunners the services of Laurent Koscielny, who starts a three-game ban for his sending-off.
Gabriel will be sidelined for six-to-eight weeks, meaning he could miss the start of pre-season.
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Shkodran Mustafi could also miss the Wembley showpiece with boss Arsene Wenger confirming at his Wednesday press conference that the Germany international is "still sick."
Gabriel's injury saw Per Mertesacker come in for his first action of the 2016-17 season and Wenger hinted that he may have to move away from the back-three he started to use towards the end of the Premier League campaign.
Rob Holding is the only member of Wenger's trio who remains fit, although the Frenchman has also used full-back Nacho Monreal in the middle at times.
Wenger said: "Gabriel is out for six-to-eight weeks. We had a scare about his cruciate, but it is only medial knee ligaments so positive is that he avoids surgery. But of course, he is out now until the beginning of August.
"Shkodran Mustafi we have some worries because he is still sick at the moment. He has not trained yet.
"This just shows you how unpredictable football can be. We played at home where your mind is on attacking, and it is a day when we lost two centre-backs.
"It's unbelievable and unpredictable and we are hit hard in a position where we need to be strong on Saturday. We have to find solutions and hopefully I can find those solutions.
"I have to decide on Saturday [whether to change to back four] and we'll test that in training until then.
"(Alex) Oxlade-Chamberlain is in contention because he is back in training."