Tom Anderson and Ben Whiteman are doubtful for the trip to Sunderland on Good Friday.
Anderson returned to the heart of the defence in impressive fashion at Bradford City last week but missed Saturday’s 2-0 victory over Plymouth Argyle with a calf strain.
Whiteman had hoped to be back in contention for the Stadium of Light visit but is yet to resume full training after suffering ankle ligament damage during last month’s draw with Barnsley.
“We were gutted for Tom,” said McCann.
“He trained on Tuesday and he felt his calf a little bit after the session.
“He reported it to the physio, didn’t come in on the Wednesday because we had Wednesday off, and then came in on the Thursday because he felt good again.
“He trained on Thursday and got through most of the session and just felt it at the end.
“He has had a scan and it’s nothing serious. It’s just a slight strain that will keep him out for five to seven days.
“We’ll see how he is.
“He’s not going to train for most of the week but if the physio gets some good work into him then he may be involved.”
Whiteman has undergone revolutionary MBST treatment – which stimulates cell regeneration – in a bid to quicken his recovery but the midfielder is still feeling the effects of the injury.
“Ben’s probably similar to Tom,” said McCann. “We’ll see how he goes.
“He’ll probably not train during the early part of the week and we’ll see later in the week.
“He’s running, he’s twisting and turning, it’s just when he’s passing the ball that he’s feeling it a little bit.
“It’s down to Ben and when he feels ready really.
“We’re all pleased with how well it’s settled down, now it’s just about getting that pain-free element to his training.”