Mesut Ozil is now back in London and working with the club’s medical team after leaving the German national squad on Wednesday.
The Arsenal medical team informed their German counterparts of the playmaker's knee problem on Sunday night after the match against Chelsea at Stamford Bridge.
Arsène Wenger knows he will be without the 25-year-old for at least two months.
“When he arrived with the German national team, they didn’t think it was a lot at the start,” the manager said. "He was supposed to practice on Wednesday but, in the end, he said that wasn’t possible for him.
“Then he had a scan and it was bad news. We have our own specialist giving us his opinion after reading the scan and examining Mesut. We will follow our own recommendations.”
“Theo is not too far away now,” said Wenger. “Serge has been out for a long, long time and Theo has also been out for nine months, so it’s good to see them back. They’ve worked very hard and they’re very dedicated. They are back in the group on a daily basis and that’s very good news.
“For Ramsey it's day 13 today and I think it will be day 21 before he is back into training. Arteta may be back with the group late next week.”Copyright 2016 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source