"You don't disrespect [future] Hall of Famers like that," Mitchell said. "That's just absurd."
Polamalu is expected to be healthy enough to play Saturday (8:15 p.m. ET, NBC) when a team he has tormented over the years visits Heinz Field. Polamalu has practiced both workouts this week and defensive coordinator Dick LeBeau said he anticipates the eight-time Pro Bowler suiting up against the visiting Baltimore Ravens in the AFC wild-card playoff.
Polamalu has missed the past two games because of a knee injury, and Will Allen has started in his place at strong safety.
The secondary has been a strength during that stretch and LeBeau acknowledged Thursday that Allen played one of his better games for the Steelers last Sunday night. The 11th-year veteran recorded seven tackles and made several key plays early in the Steelers' 27-17 win against the Cincinnati Bengals.
"There's only one Troy," LeBeau said, "but Will Allen is a very good football player. I think with both in there we have some good safeties."
What makes Mitchell, Pittsburgh's starting free safety, scoff is the notion that Polamalu is a liability on the field as the Steelers pursue a seventh Super Bowl title.
Mitchell, who is in his first season with the Steelers, said Polamalu has had a significant impact on him.
"His selflessness and his humility, that's what makes him a great football player," Mitchell said. "How can I make my teammate better? What can I do to put him in a better position? When you start thinking like that, giving more of yourself, more of your mind, more of your body you become a better player because you're thinking about something bigger than just yourself, and I think that's the one thing I've learned from Troy that's made me a better player.
"It's not about my jumping a route and getting a great interception. It's about me staying over the top and somebody else gets the interception because I took away the deep pass. That is what makes him a Hall of Famer."
Mitchell said any perception that Polamalu hurts the Steelers' defense by freelancing is way off base. He said there is a method to the perceived madness that is one of Polamalu's hallmarks.
"If you don't know him you think he's a guy making all kind of crazy plays but you talk to him and get to know him as a person and understand how he thinks you're thinking, 'Wow," " Mitchell said. "It's really mesmerizing."
When asked if Polamalu, who is 33 and in his 12th NFL season, can still play, Mitchell did not hesitate to answer.
"No question," he said. "No question."