The Northern Irishman has revealed that the winger, who withdrew from the England squad with injury, is a doubt for his side's next Premier League game at the Stadium of Light.
The wide man was recently forced to withdraw from the England squad due to injury and, although he has returned to training, the Northern Irishman revealed he is uncertain over his fitness.
“Adam is progressing quite nicely, which is good, but I don’t know yet,” O’Neill said when asked about Johnson’s chances of being fit. “He’s done some work with a couple of the other injured players, including Phil Bardsley and Wes Brown.
“It’s too early to know whether he’ll be available but it would be great if he could make it.”
The 25-year-old joined the Wearside club in August after falling out of favor with Premier League champion Manchester City.
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