The striker has been out of action since April with the problem, understood to be bruising on the bone, and is not even fit to train never mind play
The Gunners striker is suffering from the same knee problem which kept him out at the end of last season.
Understood to be bruising on the bone, it has flared up again.
There is no exact timescale on Welbeck's return, but he is hoping to be fit for the Emirates Cup tournament at the end of this month.
But Welbeck has yet to start pre-season training - and missing the Asia Trophy in Singapore next week is an indication that he is not yet fit to train never mind play.
Stuart MacFarlane
He had been hopeful of returning before the end of the campaign but has suffered several setbacks - and this latest news will be a huge disappointment to him.
It will also be a concern to England boss Roy Hodgson, as Welbeck is one of the first names on his teamsheet when available.
Arsenal are competing in the Far East tournament with Everton and Stoke.
The prospect of him missing pre-season training will be of greater concern to boss Arsene Wenger.
The Gunners' manager has staggered the returns of some players and has already said that star forward Alexis Sanchez will miss the start of the season after his involvement in the Copa America only ended last Saturday.
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