The problem with starting a rookie quarterback is just that.
He's a rookie and he's starting.
A rookie quarterback like Justin Fields has not played before in the NFL and it's a different game than college, but when he faces the Cleveland Browns on Sunday as injured Andy Dalton's replacement he'll have an equalizer that some rookie quarterbacks may not possess.
It's that 4.4-second speed coach Matt Nagy droned on almost incessantly about during offseason work and training camp. There might even be more about Fields besides speed that coaches are just starting to realize.
"Justin is a dangerous weapon with his arm and with his legs as well," running back David Montgomery said.
Justin Fields' Speed Factor
Nagy and the offensive coaches have tried to get Fields prepared to face an NFL defense from beginning to the end of a game all week for the first time, and are learning more about their rookie as they've gone along.
The speed he has running is something they knew from the beginning, but finding different ways to use it has been the order of the day at Halas Hall this week.
"The traits that he has when he escapes the pocket, the way the defenses gotta plan for who he is because of his speed as a quarterback, that's rare at the quarterback spot to be able to throw like he can and do that," Bears coach Matt Nagy said Friday after completing a week of work. "So there is excitement for us.
"With that said, as your backup when he comes in like that sometimes you can get in a position in that quarterback room where you have a guy that doesn't have all that, doesn't have the experience, doesn't have the traits and it can be difficult."
Fields will have it. He can turn nothing plays into something with his speed and the Browns defense must cope with this.
The Bears just have to hope there aren't many of those "nothing" plays because with rookies who lack experience facing defenses or running their offense those can often occur often.
One way they might see Fields using this speed is keeping on an RPO play instead of handing off or passing. They haven't done a lot of this.
"When you've got a kind of guy who has that kind of, like, skill set in using his legs, you have to respect it," Montgomery said. "Like I said, I'm excited to see what that's gonna bring to the field on Sunday."
Montgomery said he can tell Fields knows how to run the zone read well and decide when to pull the ball or keep it.
"Sort of, because I was in that quarterback position as well," Montgomery said, thinking back to his high school days.
Montgomery also runs that play as the quarterback in the Bears wildcat at times.
"So I kind of know the mesh point," he said.
Realizing Justin Fields' Potential
The week of work has made Nagy better aware of what his rookie can do—how they might use his speed in the offense. It's also made them aware of what he can't do, yet.
"There's going to be a lot of good stuff that we can do with this offense, but that does take a little bit of time," Nagy said. "You see that as you go. There's little things that we're learning too, like this week, with him getting all the reps in practice. There's things that we're seeing that maybe we didn't see in the first two weeks, because he wasn't getting those 1 reps.
"That part is good. That's healthy, because now, as long as we take that to him and say, 'Listen, when you do this, this, or that, this is what you've got to get a little bit better at, this is what you're doing well.' Let's go back and watch the tape and see why we were a little bit late on this throw.' And for him, alls he's doin' is, he's building blocks of a foundation of how he's getting better."
Before Fields was running scout team, but not this week. It's obviously increased his speed of development.
"That's the beauty of him having these great reps in practice, which is what he wasn't getting," Nagy said. "But now he has an opportunity to do it, so we've got to take advantage of it."
Since the start of the season media types have been trying to get Nagy to compare Fields with Michael Vick because he runs fast like Vick did and he can throw, and also because Nagy coached Vick for a few years in Philadelphia.
This would be a colossal disappointment for Bears fans if all Fields does is reach Vick's level, a lifetime 80.4 passer rating with only 56.2% completed and 7.0 yards per attempt, not to mention a habit of fumbling.
Fields has the potential to be a far more accurate passer than Vick ever did, and he has been showing he can pick up offenses and defenses the way an elite passing quarterback does.
"At the same point in time, what I love about Justin is that he has the ability to process these plays and learn in meetings, see stuff on tape, take it out to the practice field and put it into action," Nagy said. "And then, if it's not right, try to fix it and improve it the next day.
"We've had Wednesday, Thursday, Friday where, in my opinion, he's gotten better every day, just a little bit. That's all you want to see from him is just a little bit of, slightly improving every day."
Steady, incremental improvement is what the Bears wanted to see from Mitchell Trubisky.
Now, they can only hope Fields has improved enough steadily through the week to beat a strong NFL team on the road.