Johnson's absence makes it a double blow for Neil who is set to be without striker Sean Maguire until the new year."DJ's got an issue with his quad," said Neil, speaking at Thursday morning's pre-Blackburn Rovers press conference.
"We'll find the full extent of the injury on Friday.
"The most frustrating thing was he getting into good form and everything was starting to click into place.
"It doesn't look like one where he's going to be back next week.
"It's difficult to put a timeframe on it and I don't want to jump to conclusions but it's one where we're going to be missing him for a little bit of time."