This Sunday, Tony Romo, Jim Nantz and Tracy Wolfson will face their biggest test as a trio when they call the AFC Championship Game between Tom Brady's Patriots and Blake Bortles' Jaguars from Gillette Stadium (CBS 3:05 p.m. ET). And a year from now, if everything stays on course, Romo will finally reach a Super Bowl, albeit as an announcer rather than a player, as CBS has the rights to Super Bowl 53 in Atlanta.

Who knows how much more popular he'll be by then.

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At the moment, with every big game telecast Romo does, he is rewriting his legacy from that of a talented but oft-injured quarterback with only two playoffs wins as a Dallas Cowboy, to the wave of the future in NFL TV.

Not since John Madden burst on to the scene with Pat Summerall nearly four decades ago has a new NFL color analyst been so lauded by fans, critics and TV competitors alike. And in just one season with play-by-play partner Nantz and sideline reporter Wolfson, Romo has CBS' No. 1 announce team challenging NBC Sports' Cris Collinsworth/Al Michaels/Michele Tafoya and Fox Sports' Troy Aikman/Joe Buck/Erin Andrews for the heavyweight title of best NFL broadcast team.

The unsung hero behind Romo's meteoric rise has been Nantz, who has been equal parts coach, mentor and friend to the TV novice. But during a media call Tuesday to discuss the game, the veteran sportscaster gave all the credit to his rookie partner. In fact, Nantz said he realized Romo's TV potential the first time they sat down to tape a practice game eight months ago, at the CBS Broadcast Center in New York. To Nantz, Romo's overnight success is "no surprise" at all.

"This is going to sound crazy to say, but by the time we finished the fourth quarter of that [practice] game, I thought he was ready to go on the air," said Nantz. "His instincts are off the charts."

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Romo's knowledge of current players, schemes and play-calling is next level, according to Doug Gottlieb, the former CBS college basketball analyst turned Fox Sports personality. Romo's ability to translate NFL jargon into layman's terms creates "Ah-ha" moments of understanding for TV viewers, and his infectious love of the game and ability to predict plays before they happen have endeared him to many.

"Romo is Tony is 2017 football," said Gottlieb.

They say success has many fathers but failure is an orphan. Against that backdrop, it's easy to forget just how much of a gamble the risky Romo hire was for CBS Sports boss Sean McManus.

Phil Simms, the two-time Super Bowl-winning former Giants quarterback, had been ensconced as the Tiffany network's lead game analyst for nearly 20 years. Romo, on the other hand, had zero broadcasting experience. CBS took a beating publicly when it announced Romo's hire on April 4 without comment from the vacationing Simms -- leading son Chris Simms to fly to his dad's defense.

Some critics wondered if Romo would fold under the pressure of calling both Sunday afternoon and Thursday Night games in his first year. Or if CBS should have eased him into the job via a three-person booth. Others expected Romo to follow the siren song of Cowboys sugar daddy Jerry Jones and return to the NFL — ala Jay Cutler, who spurned the No. 2 analyst job at Fox Sports to join the Dolphins this season. There were the inevitable Twitter jokes/memes, such as Romo would be the first announcer to break his collarbone in the broadcast booth.

McManus and CBS ignored the naysayers. Their faith was rewarded. Now Romo is the toast of TV sports.

Sports Illustrated media columnist Richard Deitsch named Romo SI's 2017 "Media Person of the Year." Wrote Deitsch: "Having currency (Romo was on the Cowboys’ roster until April) does not always translate into astute analysis but Romo’s knowledge of the league — specifically the formations and fronts of teams and how an offense attacks a defense — made him an invaluable resource for NFL viewers."

Media writer John Ourand of SportsBusiness Journal wrote Romo and Nantz "have been the most talked about broadcast team this NFL season." When Ourand asked Nantz if Romo or Cutler would be the better rookie broadcaster, Nantz "just sat back and laughed." Awful Announcing pointed out Romo is a viral sensation for his Nostradamus-like ability to call plays in advance. "It's hard to imagine how the Romo experiment could be going any better for CBS."

And Cutler? With the Dolphins missing the playoffs, the surly 34-year-old QB's future is in question. He reportedly doesn't want a backup job. If Fox hires him back, he'd be lucky.

Romo, on the other hand, has been a delight to Twitter, which is filled with examples of him calling out runs, passes and blitz before they happened. But there's more to Romo than his "Amazing Kreskin" ability to predict plays, Nantz noted on the call.

"He has multiple pitches, so to speak. A lot of folks came off the first real broadcast and tried to paint a picture of him as this incredible play-caller. But there’s much more breath to his skill level than just that," said Nantz. "He’s always ahead of the game. That doesn't mean calling the plays every single time. There are roughly 130 snaps during a football game. If he was two or three times in a game to foreshadow exactly where the ball’s going to go, that’s a small percentage. I don't think he ever got enough credit for the other 127 snaps that were taking place in a game. Because he was brilliant over all of those too, as far as his analysis."

Point taken. That's not to say Romo hasn't made his share of rookie mistakes.

Early on, he seemed to mumble some calls, and shout others, depending on the noise level of the stadium. In his eager beaver way, he sometimes stepped on Nantz' actual play calls. Two weeks ago, he described the Jaguars' godawful 10-3 wild card win over the Bills an "unbelievable" game, even though the pathetic performance by Bortles and Tyrod Taylor of the Bills set NFL passing games back a 100 years, tweeted ESPN's Louis Riddick.

That game showed Romo is not yet ready to rip his fellow QBs. Until he does, he'll never fully embrace the TV Dark Side.

Still, here's the scary prospect for Collinsworth, Aikman and whoever ESPN hires as color analyst to succeed Jon Gruden on "Monday Night Football." Romo will only improve as he gets more reps with Nantz, Wolfson, CBS' lead NFL producer Jim Rikhoff and game director Mike Arnold. He's already planning a sit-down with Nantz and the team this off-season to examine ways to improve.

Quite rightly, Romo doesn't want to be seen as a one-trick pony, predicting plays before they happen. You do that one too many times, you end up dead wrong -- and an object of ridicule on social media. Picking up on Nantz' pitching analogy, Romo said he wants to be seen as a guy with a lot of different pitches, not just a fastball. He and the CBS team are always tinkering, "Hopefully we’re not the same every week," said Romo. "That’s what we talk about sometimes. Changing it up."

Romo and Nantz are friends as well as TV partners, talking often about football and their shared love of golf. Romo will serve as an on-course reporter at several CBS tournaments this year. The 58-year old Nantz looks "reinvigorated" working alongside his younger partner, according to Gottlieb.

Fairly or unfairly, the 62-year old Simms became as much of a target for online ridicule as mistake-prone rules analyst Mike Carey. Like a good soldier, Simms has adjusted to his new role on "The NFL Today," showing off a nice sense of humor. After calling 250 games and multiple Super Bowls with Simms, Nantz has nothing but respect for his old partner.

“We never had a cross word. It was a great time. I can’t speak to whether I feel revitalized. I take every on-air relationship on its own. Working as many events as I do, whether it be the NFL, or college basketball, or the PGA Tour and the Masters, I work with a lot of different partners," said Nantz. "In the span of 33 years now at CBS, I’ve worked with a lot of different, great analysts. I’ve been fortunate in my football life to have been the beneficiary of that. So I’m going to take my time with Tony and just have that as a stand-alone event. It’s been special. It’s been great to see the reaction Tony has gotten from Day One. To see the reaction that all of us have gotten as a team. We’re energized as a unit. Tony has made us all better. I think it’s the start of a very long run."

If CBS took a gamble on Romo, he also took a gamble on CBS.

It was a big decision for Romo to leave America's Team after 14 years and at a time when older QBs such as Brady and Drew Brees are still at the top of their games. Football players are creatures of habit. Even Nantz wasn't sure how Romo would adjust to being in the broadcast booth and production meetings rather than on the sidelines and in locker rooms.

"This was a big leap of faith for Tony," said Nantz. "The fact that he’s had a good time, more than a good time, I know he’s had a great time, and enjoyed every part of the process, I take a lot of satisfaction out of that. I really do."