The Black Cats appealed against the red card the Gabon international received for his challenge on Cardiff’s Junior Hoilett last weekend but were unsuccessful and Ndong, who has been linked with a move to Watford, is now set to sit out against the Tigers, Birmingham and Ipswich.
Marc Wilson is a doubt after limping off at Cardiff with a recurrence of a groin strain, while Adam Matthews, an unused substitute in South Wales, has been unable to train this week because of a calf injury and Aiden McGeady is working his way back from a similar problem.
Paddy McNair is not yet ready to return from his groin injury, while Lamine Kone (knee), Darron Gibson (groin), Jonny Williams (shoulder) and Duncan Watmore (knee) are still sidelined and Jack Rodwell remains out of the picture amid uncertainty over his future on Wearside.
Hull striker Will Keane is in contention to make his long-awaited comeback following a 14-month injury lay-off.
The former Manchester United forward, who sustained the second serious knee injury of his career in November 2016, will be included in Nigel Adkins’ squad.
Morecambe have no fresh injury concerns ahead of Tuesday's Sky Bet League Two home clash with Colchester.