Goalkeeper and American international given green light to return to training later this week
Andrew Longeran and Tim Ream have both been given the all clear after being stretchered off against Nottingham Forest at the weekend.
Lonergan was kept in hospital on Saturday night after being knocked out and receiving lengthy on-field treatment following an innocuous collision with Dexter Blackstock.
Scans have since given Lonergan the all clear and, whilst he will definitely miss Tuesday’s game at Middlesbrough, he could now be back in training towards the end of the week ahead of Saturday’s home game against Brighton.
Ream meanwhile has also been cleared of serious injury after colliding with a post at The City Ground.
Scans on the American’s lower back have come back clear, though again, he is expected to miss out on Tuesday’s trip to Middlesbrough.
Neil Lennon said: “Andrew had a bit of concussion. He's a little sore around the chest and neck area. We'll see how he is ahead of Saturday.
“Tim’s scan has come back clear, though we don’t expect him to be available for the Middlesbrough game.”