Alese and O’Nien have both undergone surgery on shoulder injuries this summer, Cirkin is still nursing the wrist problem that has bothered him since last November and Leo Hjelde has an Achilles issue.
All four players will miss the opening three games of the season against West Ham, Burnley and Brentford, leaving Regis Le Bris short of defensive options.
The injury setbacks means Dan Ballard and Jenson Seelt are the only fit senior central defenders on the club’s books, with Sunderland prioritising the addition of a centre-half in the coming weeks. Chris Mepham returned to Bournemouth at the end of last season after his impressive loan spell.
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Meanwhile, Sunderland have confirmed Habib Diarra is available for selection when the Black Cats face South Shields in their opening pre-season friendly on Saturday.
But Sunderland are still waiting for international clearance for Noah Sadiki and Chemsdine Talbi, so the pair won’t be involved at the 1st Cloud Arena.
Simon Adingra and Reinildo will also miss Saturday’s game.
Adingra’s move was only confirmed on Thursday night, while Reinildo hasn’t yet linked up with Sunderland’s squad having been given an extended summer break after participating in the FIFA Club World Cup with Atletico Madrid.
He will join the squad when they return from Portugal later this month.