The arrival of Spain star David Raya in the summer has seen Ramsdale suddenly demoted to second choice this season.
This is despite the England goalkeeper recently agreeing a new contract after helping the Gunners challenge for the title during his debut season at the Emirates.
Speaking to The Highbury Corner podcast, Ramsdale's father Nick admitted his son has 'lost his smile' and questioned Arteta's lack of any explanation.
It comes after the player's dad had a public row with Liverpool legend Jamie Carragher for 'laughing' at the 25-year-old shot-stopper.
Nick said: "When I spoke to Mr Arteta on the phone before he signed Aaron, he said he wanted Aaron. But now, you know, David Raya's back on the market and he's had David Raya.
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"Why would you extend a goalkeeper or any player's contract and then two months later, or three months later [make a move on someone else?].
"Aaron is going to be the cup goalkeeper, and David Raya is going to be the main man unless something happens, an injury or a sending-off. Aaron's got to live with that and he is living with that even though he's not been told it by anybody."
Nick continued: "Aaron's lost that smile to when he was holding onto that ball at this moment in time.
"And it is difficult. It really is difficult to see him there and we all keep saying you need to keep smiling."
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However, Ramsdale's dad insisted there is no issue between his son and Raya, whose recent performances have been questioned in some quarters.
"David Raya is a great goalkeeper and it is not his fault," Nick added. "He's just come in as a goalkeeper. Aaron says he is a lovely guy and he works hard with him and Aaron's trying to help him as much as he can to settle in with the squad.
"It's possibly the way it's been done. Not knowing the reason why, and this is me because we don't know why. Again, Aaron is working as hard as he can. He's trying to do his best for the squad. He's upbeat and he'll do everything for Arsenal to try and win the league."
When asked about the criticism Raya has faced, Nick added: "You've got to give the guy a chance for God's sake. Even though the way it's been done, in my eyes, it's been wrong and we can talk about that but it's the decision.
"Really and truly we've got to get behind David Raya. He's part of the family now. Whether it's only until May or June of next year. It won't be, it'll be longer in my eyes, but that's by the by."