It is time, Chicago.
The announcement came days after Nagy declined to name a starter for Week 3. After not being scheduled to speak to the media Wednesday, Nagy said it was important to "move forward" and make the announcement Fields would start.
"He prepares well. First time to truly prepare as the starter," Nagy said of Fields.
Asked how ready he feels to start, Fields replied, "I think I'm ready. I've been preparing for this moment for a long time."
Nick Foles will be the backup Sunday.
Nagy declaring Fields the starter came with a caveat that the coach expects Dalton back when he's healthy.
"When Andy is healthy, he's our starter," Nagy said of Dalton, who is considered week-to-week.
It's the same refrain we heard from former Los Angeles Chargers coach Anthony Lynn last year when Tyrod Taylor got hurt in Week 2, giving way to eventual Offensive Rookie of the Year Justin Herbert. It's not unusual for a coach to shade toward a veteran, particularly after an injury, leaving himself an out down the line if the rookie struggles.
It's on Fields to perform and make the decision perfunctory.
"I think every time I go in, I have that mindset," Fields said when asked if it's his opportunity to win the full-time job. "Of course, I'm going to go out there on Sunday and play my best and, of course, just try to come out with the win. That's my main focus. My main focus isn't winning the starting job. I think that's going to come with time. My main focus right now is just to prepare the best I can and go out Sunday and execute at a high level."
Taking over for Dalton midway through Sunday's victory over the Cincinnati Bengals, Fields experienced the ups-and-downs most rookies go through in their first extended appearance. There were some rockets from his right arm, a gorgeous deep shot Allen Robinson dropped that should have been a TD, and, of course, some magnificent scrambles. There were also negatives, like not seeing a defender drop into coverage, leading to an interception.
Given that he was tossed into the fire midway through the game, without taking the majority of the reps in practice or having a game-plan tailored to his skill set, it was an encouraging performance from Fields, even if box-score watchers might scorn.
The rookie provides Nagy's offense an array of options Dalton just doesn't. The mobility brings the threat of read-options, RPO, and more rolled pockets. Fields' livelier arm should extend the offense better beginning in Week 3.
"He was pretty stoic. ... He's a guy that has a lot of confidence in himself in a lot of ways," Nagy said of Fields' reaction to being named the starter.
There will be growing pains as the rookie learns to speed up his processing. But allowing Fields to grow and learn in live battle is the best long-term strategy for the Bears, who've long searched for a dynamic franchise game-changer.
When Chicago traded up in the draft to snare the Ohio State quarterback, it was only a matter of time before Nagy relented and made him the starter. But, after insisting all offseason Dalton's play would determine when that might be, an injury took it out of the coach's hands.
Fields' play will decide whether Dalton stays on the sidelines.
"Justin's worrying about right now," Nagy said. "Justin's worried about trying to help us beat Cleveland. I've talked about it this entire time that we're not going to get into that 'what if' game."
Most prognosticators pegged Week 4 for a potential QB change. Dalton's injury sped that prediction up by a week. Facing a menacing Cleveland pass rush, led by Myles Garrett and Jadeveon Clowney, provides a challenge for Fields.
In a sink or swim league, the rookie just got tossed into the deep end. Finally.