Ryan joined the Gunners on loan from Brighton last week and will stay with them until the end of this season.
The Gunners were in the market for a new goalkeeper this month to provide competition for Bernd Leno.
They opted to swoop for Ryan, with his loan deal containing no option for Arsenal to make the move permanent.
The Australian has slipped down the pecking order at Brighton and has just one year left on his contract at the Amex Stadium.
Asked if Ryan’s move could still be made permanent in the summer, Arteta said: “I don’t know, he just arrived.
“At the moment it’s a loan deal, he still has a contract with Brighton and we will assess it – see how he performs, how he adapts, what we need in the future. It’s still too early to decide.
“He’s a player that knows the league really well. He’s played so many games, he’s got international experience, he’s at the right age, he’s been competing regularly until December and we felt with the departure of Matt Macey [to Hibernian] we needed another keeper in the team to be more protected.
“So we looked at the market, we wanted a loan deal and we decided to go with Mat because he had the right profile for us.”