Mikel Arteta cast doubt over David Raya's availability for Sunday's Premier League clash against Manchester City.
The Gunners' first-choice goalkeeper was absent through injury on Wednesday as they secured automatic qualification to the Champions League round of 16 with a 2-1 win at Girona.
In Raya's absence, Neto made his Arsenal debut having arrived at the club last September on a season-long loan from Bournemouth.
The 35-year-old was at fault as Girona took a surprise 28th-minute lead through former Tottenham Hotspur forward Arnaut Danjuma, but the Gunners recovered through Jorginho's 38th-minute penalty and a fine left-footed strike from teenager Ethan Nwaneri.
Arteta didn't reveal the exact nature of Raya's injury and told reporters after the game: "He certainly could not play and he's injured and that's it. We'll see how it improves."
Pushed on whether Neto was able to deputise over a longer period, Arteta said: "Yes, that's why he's here, to do that job and he's done it for 20-odd years in his career.
"I'm very happy, first of all, that he played. It's been seven months, eight months almost, since he played his last competitive match and it's not easy, so I'm very happy that he played and we won again."
ESPN reported earlier on Wednesday that Arsenal had a bid rejected for Ollie Watkins by Aston Villa. A deal appears to be complicated by Al Nassr reportedly closing in on an agreement for another Villa forward, Jhon Durán but the Gunners will consider whether to return with an improved offer.
Arteta said: "You know, I cannot talk about any of that. My confidence is that we have an amazing club and people working always to try to improve and let's see what happens."