Former Leeds United youngster Romario Vieira will not be joining Doncaster Rovers.
The 20-year-old midfielder spent time on trial at Rovers this summer after being released by Leeds.
“Romario’s left the club,” said McCann.
“Romario was more of a [long term] project and we felt, looking at the young lads who we’ve got at the club, it wouldn’t be the right thing to bring a player in that was on par with a Cody Prior or a Jacob Fletcher or a Morgan James.
“We’ve got to believe in the players that are here. They’ve been given pro contracts for a reason.
“We’ve got to get amongst them and when they join in with the first team we’ve got to make sure they’re ready for the first team.
“That was the reason I didn’t do it.”