News broke that the 30-year-old had made himself unavailable for selection just before Sunderland were set to take on Stoke in the Championship on Saturday.
Pritchard will see his contract expire at the end of the season and was already looking likely to leave.
But the player and club appear to have hit a wall with relations breaking down.
Pritchard is now looking to leave the Stadium of Light as soon as possible while Sunderland posted a statement on Saturday afternoon.
It read: "On Friday morning, Alex Pritchard informed the Club that he was no longer available for selection and he subsequently withdrew from today's matchday squad.
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"The midfielder also expressed his desire to leave SAFC with immediate effect.
"The Club will be making no further comment at this moment in time."
Pritchard signed for the Black Cats in 2021 and helped the club earn promotion from League One to the Championship.
He had proved a key member of the squad, whose experience was vital last season as Sunderland reached the play-offs.
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The attacking midfielder came up through the academy at Tottenham, where he made two Premier League appearances before loans away at clubs such as Peterborough, Swindon Town, Brentford and West Brom.
Norwich snapped him up in 2016 before joining Huddersfield in January 2018, helping them stay in the Premier League before being relegated a year later.
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Sunderland fans are not happy with the club at the moment after Tony Mowbray was sacked earlier this season.
New boss Michael Beale has not got off to the best of starts and already has the fans on his back.
After reaching the play-offs last season, a repeat of that scenario looks unlikely at the moment with the club 10th in the table.