Getty Images

In the Cleveland locker room this summer, Johnny Manziel was the typical rookie. He was mostly quiet, players told me then and now, and those players—then and now—make sure this is emphasized: Manziel has been a total professional.

There was one meeting where Manziel was late, but none of the players I texted with said they knew of any other issue.

"I've been waiting for this cocky ass---e to show up," one player told me this week. "It never happened. All I see is a pro."

Manziel and Brian Hoyer were informed on Monday that Manziel would start Week 15. I can tell you there are some Browns players—a few—who believe that Hoyer should remain the starter. That is true. But there is also widespread support for Manziel. They believe he deserves the chance.

In a statement released by the team, Manziel was quoted saying:

I'm very appreciative of the opportunity that Coach Pettine and the coaching staff have given me to be the starter on Sunday. I've tried to spend my entire season learning what it takes to become a pro and it's been great to watch Brian because he knows what it takes. I've prepared every week to be ready to help the team however possible and my focus has been on improving every day. I'm very excited to get out on the field with my teammates on Sunday and to have the opportunity to make the Dawg Pound proud.

The Browns had to do this. They had to. But it is not without risks. I'm convinced Manziel has the talent to be a good NFL quarterback, but I'm not convinced, yet, he has the maturity to handle it.

Again, the Browns needed to do this. Hoyer has led Cleveland to one touchdown in his last 29 drives. That is a Jaguars type of putridity. My guess is also that unless Manziel is absolutely terrible, this is the end of the Hoyer era. See you with the Jets next season, Brian.

Brett Carlsen/Getty Images

What Manziel provides is electricity. You are going to see the typical Johnny—electric plays, big plays, good athleticism. Look for Manziel to also make sure one of the best weapons in football, wide receiver Josh Gordon, gets the ball often (this week, Gordon might actually hold on to it). There are going to be numerous positives, including the fact Cincinnati will have to prepare for a multi-dimensional threat.

That's the good news. We are going to see Manziel, overall, do well. This is the start of his era. He has ability. He's smart. He'll do well.

How well depends on the other part of football—the mental part.

We have watched as the sport destroyed the minds of young players who showed immense promise. We've seen the NFL annihilate Robert Griffin III after he initially broke through. The reason for that annihilation was Griffin's maturity. It wasn't there. Griffin let his success get to his head, and then the idiot owner undermined Griffin in the locker room by being too cozy with him. Griffin compounded the problem by not having a strong work ethic.

In San Francisco, Colin Kaepernick has disintegrated mentally. He looks lost, and he hasn't been well served by his head coach.

There are successful stories of young quarterbacks evolving into great ones, but most of the time the young ones get chewed up. There are more Ryan Leafs than Andrew Lucks.

The Browns are a perfect example. It's like the "Justin Bieber Curse" started in Cleveland and never left. It's been a quarterback graveyard: Hoyer, Campbell, Weeden, Lewis, McCoy, Wallace, Delhomme, Quinn, Anderson, Dorsey, Gradkowski, Frye, Dilfer, Garcia, Holcomb, McCown, Couch (Couch…LOL), Pederson, Wynn and Detmer.

John Bazemore/Associated Press

That's just…sad. Factory of Sadness sad.

This is why the Browns coaching staff has to tread carefully. If it doesn't, Manziel will become another statistic. It wasn't a terrifically big deal when Manziel was involved in some sort of dustup recently, but it is also fair to say Russell Wilson, Tom Brady, Peyton Manning, Andrew Luck and Aaron Rodgers haven't had those kinds of headlines. The worst headline Peyton has generated is calling his kicker an idiot. The great ones in this league stay out of trouble.

With Griffin, the fame eroded his work ethic. He stopped studying, stopped caring about football and started caring more about the RG3 brand. My concern is that Manziel falls to the same trappings.

But so far, at least in the NFL, that hasn't happened. One Browns player put it this way: "I've come to trust him. I think a lot of guys do."

He's earned it. For now.

Mike Freeman covers the NFL for Bleacher Report.