"My biggest deal was my gut telling me that I needed to impact the team by changing the dynamic," Crennel said, adding that the move isn't about placing blame on Cassel.
"I am not saying Matt Cassel is the reason we are where we are," Crennel said, "because the stroke of that brush is a broad stroke."
Cassel wasn't pleased to learn he was losing his starting spot after missing the Week 6 game against the Tampa Bay Buccaneers.
"Am I going to say that I'm happy about this situation? Absolutely not," Cassel said, according to comments distributed by the Chiefs. "I'm frustrated, but at the same time, I'm a team captain on this team. I care about this team, and again, as we move forward, I'm a big boy. I'm not going to hang my head. I'm going to do what I've always done and work hard, tremendously hard."
Quinn was happy Crennel gave him another opportunity.
"Look, I'm excited about the opportunity," Quinn said, via The Associated Press. "There's always pressure, but pressure is what you make of it. As a quarterback in this league, you're used to it."
Crennel is looking to light a fire under a 1-5 team that has shown limited ability to move the ball through the air, ranking 24th in passing. Crennel talked about Quinn as showing "poise" in running the offense in a 38-10 loss to the Tampa Bay Buccaneers in Week 6. Quinn finished 22-of-38 passing for 180 yards and two interceptions in that defeat, but Crennel said Quinn will take the reins "without having to look over his shoulder."
Quinn might be one of the few with that privilege in Kansas City after a rough-and-tumble opening act. This team was a popular preseason pick in the AFC West, the thinking man's counterpunch to the Peyton Manning-led Denver Broncos. Here in late October, it's clear the Chiefs could use Peyton Manning and a whole lot more.
Follow Marc Sessler on Twitter @MarcSesslerNFL.