So here we go.

Let the DeShone Kizer era begin with the Browns. The rookie will be under center on Saturday as the Browns visit Tampa Bay in the 'dress rehearsal' for the regular season that the third preseason game has become.

That means in all likelihood, Kizer will be the starting quarterback for opening day against the Pittsburgh Steelers on Sunday, September 10 at First Energy Stadium.

I didn't see this coming.

I thought for sure that Head Coach Hue Jackson would put the ball in the hands of Brock Osweiler, who had a less-than-impressive preseason showing, but still has NFL starting experience.

But it's Kizer's time.

Cody Kessler was given the job before camp started and couldn't hold it. Osweiler was given the chance to start two preseason games, and couldn't move the team. Instead, Brock will likely be moved out of town.

This is a pretty amazing development for the Browns, who are coming off of a 1-15 season with pressure to show some tangible progress this year.

As I wrote earlier this week, the Browns have had all sorts of trials and tribulations with training camp quarterback battles that end with unexpected results.

This will be the second time the Browns will trot out a rookie starting QB on opening day since 1999. Brandon Weeden got his shot in 2012. Flag jokes aside, he tossed four picks in a loss to the Eagles. He played two seasons here before being shipped out in 2014.

We've seen other teams go with rookie signal callers right out of the gate in recent years. Jameis Winston in Tampa Bay, Marcus Mariota in Tennessee, Carson Wentz in Philadelphia, Derek Carr in Oakland, Russell Wilson in Seattle, and Dak Prescott in Dallas all come to mind.

My only concern if you want to compare situations to what the Browns are about to do with Kizer is, most...if not all...of those teams had better pieces around him than what DeShone will have.

"There's a new philosophy in the NFL," the 'Voice of the Browns,' Jim Donovan told me in our Facebook Live conversation on Wednesday night. "When you draft a quarterback with a high pick, you play him right away, because the clock starts ticking and you only control that guy for four or five years."

But neither Jimmy nor I thought the Browns were in that category of thinking. Every signal given off by Jackson, or his QB coach David Lee was essentially, "we love what DeShone is doing, he's learning quickly, but he still has a ways to go."

But Jimmy sees things in Kizer that are promising. He's watched Kizer ever since the Toledo-native emerged on the scene at Notre Dame in 2015, when DeShone replaced an injured Malik Zaire and led the Irish to a come-from-behind win at Virginia.

"The thing I like about him is that he'll put the team on his back and go down the field at a clutch moment. But also I noticed that after a shaky series or two against the Giants, the mistakes were gone and he led the Browns in for a score," explained Donovan.

The clock has started.

Hue Jackson has essentially tied his future as the team's head coach to the hands of a 21-year-old quarterback. No, Kizer doesn't have to take the team to the playoffs, or even an 8-8 season. He doesn't have nearly enough around him for that.

But Kizer has to show he can be the franchise quarterback of the Cleveland Browns going forward. He needs to show improvement from now until Week 17.

Think about the team that the Browns will face on Saturday. When the Buccaneers drafted Jameis Winston in 2015, they were coming off of a 2-14 season. They played him right away, went through some growing pains, and finished 6-10. Tampa then changed coaches, added more pieces around Winston, went 9-7 in 2016, and are now on HBO's Hard Knocks looking like a team that's got playoffs written all over them.

The Browns are banking that Kizer, paired with youngsters like Myles Garrett, Jabril Peppers, Emmanuel Ogbah, Joe Schobert, among others, will be the leader of a new era.

Kizer told USA TODAY before the NFL Draft, "Why can’t I be the greatest? The only thing stopping me from it is me."

He's got the right attitude. And now, he'll have a chance to prove what he can do.

WATCH: Catch the complete conversation with Jimmy Donovan and yours truly in an expanded edition of the 'Donovan Live Postgame Show' on WKYC's Facebook Live: