Rovers saw their play-off hopes go up in smoke at Bramall Lane as they slipped to a 3-2 loss which leaves them 10 points off the top six with six games to play.
Both Coppinger and Tyson were withdrawn in the second half on Tuesday and are now doubtful for Saturday’s clash with Rochdale.
“Ty and Copps picked up nasty injuries and we tried to keep them on the pitch for as long as we could because they were causing them problems,” Dickov said. “But we had to take them off unfortunately.
“James took a whack just before half-time on his knee and it stiffened up.
“Nathan was the same, he made a run in the first half and got his foot caught and just jagged his knee so we will have to see how he is.”