Ready or not, here comes Brady Quinn.

‘‘Knock wood, I hope the guy doesn’t fall on his face,’’ Browns coach Romeo Crennel said.

How’s that for confidence?

Following another strange few days in Cleveland, where football freakishness has ruled for years, Quinn, the former Notre Dame golden boy quarterback with Ohio pedigree and pop idol looks, will make his first NFL start on Thursday night as the struggling Browns host the Denver Broncos.

The moment he emerges from the tunnel in his No. 10 jersey in front of a national TV audience, Quinn will be serenaded by chants of ‘‘Bra-dy, Bra-dy,’’ from adoring Browns fans, who fell for the first-round pick before he completed his first pass as a pro.

How long they’ll be cheering is anyone’s guess.

Crennel’s decision — at least that’s the party line — to bench Derek Anderson in favor Quinn could be a risky gamble for the underachieving Browns (3-5), who thought it was so nice to have two quality quarterbacks and now have to hold their breath that they have at least one.

Anderson’s demotion sent shockwaves through the Browns’ locker room as teammates wondered why he was being singled out for the team’s many woes.

‘‘Nobody saw it coming,’’ linebacker Willie McGinest said. ‘‘’I don’t think it’s one person why we’re losing. When we lose, we lose as a team.’’

A sixth-round draft pick, who worked his way up from No. 3 on the depth chart all the way to the Pro Bowl in three seasons, Anderson was blindsided by Crennel’s choice to hand the ball off to Quinn. Back to being an understudy, Anderson wouldn’t bite when asked if he felt Crennel acted alone in making the decision.

‘‘I respect Romeo and what he’s done,’’ said Anderson, who signed a three-year, $24 million free-agent deal to stay with Cleveland, ‘‘and that’s as far as I want to go.’’

Crennel, a former defensive coordinator, rebuffed the notion that he succumbed to public pressure in swapping QBs. But he acknowledged hearing the chants for Quinn and the boos which reigned down on Anderson after he threw a late interception in Sunday’s loss to Baltimore.

Anderson played superbly for three quarters before making a poor decision and throwing the ball directly to linebacker Terrell Suggs, who returned it for a TD to seal the Ravens’ 37-27 win.

‘‘Generally I don’t think they have my telephone number,’’ Crennel said. ‘‘I haven’t been fielding calls from the fans. I made the decision, what I think is best and what I think needs to be done.’’

Quinn’s ascension leaves the Browns with a much smaller safety net if he doesn’t live up to expectations. The team traded away two draft picks, one of them a first-rounder in 2008, to select Quinn, who didn’t make his NFL debut until the 16th game last season. He went 3-of-8 for 45 yards and led the Browns to a field goal on an 11-play drive.

He was seen as Cleveland’s future — and it has arrived.

Although he’s had a short week to prepare, Quinn should benefit from playing against Denver’s defense, which is ranked among the AFC’s worst. Seeing Anderson get demoted could be a concern, but the 24-year-old said he isn’t worried about long-term job security.

‘‘Honestly, I’m not looking past this week,’’ he said. ‘‘The biggest thing is getting a win this week. I’m not looking at eight games. I’m looking at one game.’’

While the Browns are looking for someone to throw the ball accurately, the Broncos, who rushed for 14 yards on 12 carries — Denver’s worst rushing performance in 36 years — are searching for someone to run with it.

They lost two running backs, Michael Pittman (spinal cord) and Andre Hall (hand), to season-ending injuries against Miami last week. Rookie Ryan Torain, who drew comparisons to former Broncos star Terrell Davis before breaking his elbow in training camp, is expected to get the bulk of carries against the Browns.

Gone are the days when the Broncos could count on their trademark running game to carry them.

But they’ll be going against a Cleveland defense which let Ravens rookie Ray Rice run all over them last week. Rice gained season-high 154 yards, 60 on a key run in the fourth quarter. Like Quinn, Torain, is hoping to make the most of his opportunity.

‘‘This is huge,’’ he said. ‘‘This is huge for me to show how hard I’ve worked with studying film and running plays and just being out there to help the team win.’’

That’s what the Browns are hoping to get from Quinn, who may be able to spark a turnaround and salvage a season that’s hanging by a thread.

Quinn hasn’t made a meaningful start since the 2007 Sugar Bowl, when the Fighting Irish were throttled 41-14 by LSU.

After learning he would replace Anderson, Quinn spoke on the phone to Notre Dame coach Charlie Weis, who asked him if he was ready for the challenge.

‘‘He said, ’Well, it’s the same as every week. I prepare the same every week,’’’ Weis said. ‘‘I said, ’Hey, Brady that’s a bunch of garbage. You can tell it to someone else who wants to hear that stuff.’ I go, ’you can say you’re preparing the same every week, but it’s the one thing when you’re the backup, the other thing is when you’re the starter.’’’

Crennel doesn’t know how long Quinn will keep his job. One thing is clear, though, the Browns are running out of options.

‘‘We will see how it goes,’’ Crennel said. ‘‘I dont think you can say anything is ever permanent. But if he falls on his face you have got to do something because I can’t go play quarterback.’’