The 19-year-old defender joined Spartans on a youth loan until the end of the season with Sunderland confirming the news on Friday evening.
He has made 12 appearances in Premier League 2 this campaign and will now head out on loan to the Vanarama National League North side.
Speaking to Blyth’s club website, Mitchell said: “He’s another quality player, and brings competition for places. The lad’s got good pedigree, he’s been at Sunderland since 11-years-old so is technically very good.
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“He’s a strong lad, who likes to get on the ball and play from the back, so he should fit in well with how we want to play. He’s a very good defender and can only enhance the squad.
Mitchell added, “I’d like to thank Sunderland, in particular Lewis Dickman and Michael Dodds, for allowing the deal to happen.”