Coppinger said: "We always knew the second season in the Championship was going to be tough.
"I don't want to harp on about it but if you lose two of your most influential players like Richie Wellens and Matt Mills you are bound to lose some of your momentum at a time when everyone wants to add to the squad and push on.
"Richie was a massive player for us. He used to pull the strings in midfield and with Stocky (Brian Stock) out we don't know what our best team is or what our best formation is. We've brought new players in but it takes time to gel."
Mills, last season's players of the year, joined Reading in a £2million deal in August while Leicester paid £1million for Wellens in July. Skipper Stock had ankle surgery in September and is working his way back towards full fitness.