"We could do with all three of them now - and it will be like having three new players when they return at the end of next month or early April." Lennie told the Echo.
Gabbidon is recovering from his back injury, Whalley is running again as he comes back from Medial ligament damage and Campbell is on the mend after a hernia operation.
Gabbidon and Whalley both exited the current campaign when City lost at Barnsley. Gabbidon failed to resume the gamne after half time and a few minutes later Whalley was clattered and neither have played since.