Cullen tweaked his thigh in training last Thursday, leading to the West Ham loanee missing Saturday's 1-1 draw at Bristol Rovers on the one-year anniversary of him first joining the Bantams.
Speaking directly after the Rovers draw, McCall says he felt it was more likely Cullen would have to wait for this Saturday's game at home to Bolton Wanderers before being back in contention for selection.
Previewing the trip to Fleetwood, the City chief was still of the opinon that the 20 year-old would be struggling to be fit for the fixture against the Cod Army.
McCall did confirm, however, that both Timothee Dieng and Nathaniel Knight-Percival would definitely be fit for the match despite picking up knocks at the weekend.
He said: "Injury-wise, we are ok. We didn't pick up any new injuries from Saturday.
"We will still look to make at least a couple of changes on Tuesday to freshen things up slightly.
"Fleetwood have a good squad as well so I am sure they will look to do similar.
"Nat (Knight-Percival) got a bang near his eye but he is fine. Tim (Dieng) also got a dead leg on Saturday but he has trained well today (Monday).
"Josh is still a big doubt though - we certainly won't be taking any chances with him."