The 20-year-old England youth intentional was brought into first-team proceedings last season but failed to have the impact he would of desired after an impressive loan spell at Hoffenheim.
The youngster was then offered the chance to leave the club on a temporary basis following the Gunners’ recent summer spending, but he decided to stay and fight for his place in north London.
Arteta has now praised that decision ahead of the Europa League clash against Dundalk.
"We ended up with a large squad at the end of the transfer market," the Spaniard said.
"We had a few plans in mind with Reiss.
“One of them was as well to send him on loan to get more minutes because of the competition we have upfront.
"The reality is he has been really good in training. He wants to stay here. He wants to fight for his place."
Before adding: "It was mixed reasons, Reiss was really convinced that he wanted to fight to stay here.
"When you see that willingness and that passion and that security in a player you feel tempted to keep him even though you know that opportunities are going to be restricted and he is not going to have a lot of continuity in his play.
"But things change very quickly and if he starts playing and playing well and he does what he can do, why not? He could start to play more games."
Before adding of his first-team chances: "He is going to get the chances in the right moments.
"What I am pleased with is how he has assimilated the situation - not playing a lot of minutes in the first few weeks.
"As everybody can see, things are changing very quickly. We are getting injuries. We will get more injuries because of the schedule that we have and he will get the opportunities.
"Then it will come down to him to take them or not.
"I tried to explain to him why he isn't in the team. Obviously to compare things that happened eight or nine months ago is difficult, in a positive or negative way all the time.”