The 21-year old midfielder started 13 out of 14 Premier League games this season for Arsenal but has been on the bench in the last six games.
This has been due to an injury he has been carrying all this time with many speculating the midfielder is struggling to get into the first team.
Arteta said: “Well the main reason (behind) that was because he wasn’t completely fit to play.
“He’s been carrying an issue, and that hasn’t allowed him to train regularly, to play regularly, and that was the main reason. Because in his performances, and what he did before that international break – there is no question that he was one of our more important and consistent players.
“The only reason that changed the dynamic was that – and obviously now that the team (has been) doing well, there are other players who are doing well, and have been performing well.
“That changed the situation, but I am very happy with him.”
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