The Bianconeri went down 3-1 at Bari last weekend to slip six points behind leaders Inter Milan.
That loss following the 4-1 thrashing at home by Bayern Munich which dumped them out of the Champions League.
Another defeat could see Juve slip to fourth in the standings behind Parma, but Chiellini insists that, despite the setbacks, coach Ciro Ferrara has the backing of the whole team.
"Our dressing room is more united now than ever," said Chiellini, who will miss the game with Catania with a thigh injury.
"The club, the coach and the players are all united to overcome this situation.
"Ferrara is clearly disappointed with our recent results but the whole team is behind him."