The 27-year-old has started the Premier League season out of favour at the north London side following a busy summer of transfer activity at The Emirates.
Arsenal signed Brazilian centre-half David Luiz in an £8m deal from bitter rivals Chelsea FC to push Mustafi further down the pecking order at the north London club.
Emery has opted to go with Greece international Sokratis Papastathopoulos and summer signing Luiz in their opening four Premier League games of the season.
However, the Gunners haven’t been defensively solid after conceding nine times in their opening four Premier League games ahead of Sunday’s trip to Watford.
Arsenal manager Emery has now insisted that Mustafi still has a future at the north London side.
“Mustafi decided to be here and when he did, for me, he is another player like the others in the team,” said Emery.
“Of course I respect his decision and, when he decided, I spoke with him and said ‘for me you are in the squad and I am going to work with you as with the other players’.
“I don’t know all exactly what was in his decision (to stay) but, when we spoke and he decided to be here, it was a start with him as another player in the squad.
“He is working every day with a big motivation and good experience. That is what we want, training with good experience, helping and, after, giving us his performance.”
Arsenal started the Premier League season with consecutive victories over Newcastle United and Burnley.
However, the Gunners failed their first big test following a 3-1 loss to Liverpool FC at Anfield.
Emery’s side did show character to battle from 2-0 down to rescue a 2-2 draw with Tottenham Hotspur in the north London derby in their last fixture before the international break.
Arsenal are looking to finish in the top four for the first time in four seasons.
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