The City boss had used them at Wrexham, unaware of that this was not allowed under FA rules.
"I only found out just before the kick off that we would not be allowed to have roll-on-roll-off substitutes," said Coleman to the CT.
"Apparently this is an FA ruling, although I could have sworn we had roll-on-roll-off subs at Wrexham last Saturday.
"It is ludicrous at this stage of the pre-season to force players to play a full 90 minutes.
"The main thing is not to get any injuries and this happens when players get tired.
"You should be allowed to bring them off for a spell and put them back on again. "And I'm sure the fans would not mind.
"When you are operating with a small squad you don't want to run the danger of losing players through injury.
"Fortunately we came through okay. "It was nice to win and keep a clean sheet and I was pleased with the display of our five academy lads.
"All credit to Nuneaton. I thought they had definitely improved from last year and Kevin Wilkin has done a good job."