McCann revealed he is sweating on the fitness of two unnamed players ahead of the clash, with several senior players already unavailable.
Captain Richard Wood is also touch and go for the trip to Gloucestershire but midfielder Ben Close is available and could make his first appearance of the season.
1. GK - Ian Lawlor
Man of the match last time out, Lawlor is becoming an important member of the team. Photo: HOWARD ROE
2. RB - Tom Nixon
The potential for a tactical shake-up could see Nixon return to the starting XI. Photo: Howard Roe/AHPIX LTD
3. LB - Jack Senior
Senior is making the left-back spot his own. Photo: HOWARD ROE
4. CB - Owen Bailey
Bailey might move into a back three if Doncaster opt for three centre-halves. Photo: Howard Roe/AHPIX LTD