Shearer has taken charge of first-team affairs for the remainder of the season with manager Joe Kinnear still recovering from heart surgery.
Although Newcastle are in poor form and third from bottom in the Premier League ladder, Hiddink knows there will be a fresh atmosphere in the North East following the appointment of the fans' favourite.
"You have to respect the decision made by whoever is in charge. There's always a reaction when there's something happening in a club," he said on Sky Sports News.
Get a reaction"It was the same a little bit here. Some people felt they had to make a decision and then you get a reaction, within the club and team. Everyone knows their situation.
"Of course there will be a reaction from the team and from the crowd. So we can expect a tight game and a lot of fighting spirit from our opponents tomorrow."
Hiddink is fully aware of Shearer's ability as a player and knows that his mere presence in the Magpies' dressing room will have a massive effect on his squad.
"I respect him very much. I know him as a player," he added. "He is quite a personality and will have an influence on the team.
"There will be a hectic atmosphere tomorrow. It forces us to give everything we have.
"I cannot judge whether he will stay longer than eight games, that is not my big problem. But it is always good to have big players making a transition to a manager.
"But he will not play and I will not play. It is not a game between managers.
"The instant input and change in the dressing room will give their players a lot of energy and that is an extra aspect of the game we have to deal with tomorrow."
Drogba outOn the injury front Hiddink has confirmed Didier Drogba will be missing after the Ivory Coast international damaged his ankle in shooting practice.
Jose Bosingwa picked up an injury on international duty and joins Drogba on the sidelines for Saturday's game at St James' Park, although Nicolas Anelka is fit to start.
"Drogba has a problem," continued Hiddink. "We did some exercises where he got injured. There's a little bit of a problem.
"He won't be in the squad tomorrow. We did some shooting practice and he hit the ground with his toe and the reaction was in his ankle.
"Anelka is in. He practises better and better recently, so he's in the squad.
"Bosingwa got a hamstring injury. He won't be available for tomorrow's game. We'll see what he can do up until Wednesday. Carvalho had a little bruise, but he's in the squad."