NASHVILLE, Tenn. -- Marcus Mariota may still need to prove he can play quarterback in the NFL. If he does that, his fan appeal may blast him into orbit.

That's because without having played a meaningful NFL snap, Mariota ranks as the No. 1 most appealing NFL player according to Celebrity DBI. The Tennessee Titans rookie is ahead of J.J. Watt, Russell Wilson, Aaron Rodgers and Larry Fitzgerald, who round out the top five.

Celebrity DBI is an independent index that quantifies and qualifies consumer perceptions of celebrities.

Matt Delzell managing director of The Marketing Arm, which produces the index, recently spoke to SportsCenter about the rating and Mariota’s likability.

“I think No. 1 is winning,” he said. “He comes in with a winning pedigree. The guy has won I think maybe more games than any other college quarterback. Two, I think his delivery, his demeanor, his character, the Heisman Trophy speech. Every time we’ve seen him talk, he’s incredibly soft-spoken, he’s humble and people like that. People like that especially for professional athletes.

“And again, we’re only talking about likeability and appeal. We’re not talking about awareness, which is still pretty low. But obviously that will grow as he becomes an NFL quarterback. Not playing in a huge market, so he’s not as polarizing as somebody who might be in a bigger media market.”

Mariota’s overall appeal rank on a list that includes athletes and celebrities is 517th. That’s in range of actresses Olivia Munn and Kate Mara and Baltimore Ravens coach John Harbaugh. (No. 1 overall pick Jameis Winston of the Tampa Bay Buccaneers is 3,621st.)

The index covers eight categories: Awareness, appeal, aspiration, breakthrough, endorsement, influence, trend-setter and trust.

The NFL ranking is among roughly 100 active players on the survey. The index uses 1,000 consumers and is done weekly, but different celebrities are included at different times. CBI looked at Mariota and Jamies Winston right before the draft and at Tom Brady in light of Deflategate developments.

Here's a look at how Mariota scored in each of the categories:

Awareness: Ranks at 63rd in the NFL (2,024th overall). Those surveyed are asked if they know the subject by name or face. Just under 28 percent of consumers polled knew Mariota. That ranks ranks near Nick Faldo, Abigail Breslin and John Calipari. Other NFL quarterbacks awareness score higher with Peyton Manning at 86 percent, Brady at 85 percent, Tony Romo at 63 percent, Rodgers at 51 percent and Wilson at 49 percent. Andrew Luck is around 42 percent. Awareness is weighted most heavily in the index. All the other categories are built out of only those surveyed who know the subject. So the remainder of Mariota’s scores are how he fared among the 28 percent who know him.

Appeal: "Measures likeability of the celebrity." Mariota is No. 1 in the NFL, 520th overall. Puts him with Jane Seymour, Kelly Rowland and Kevin James.

Aspiration: "Measures the degree to which people feel the celebrity has a life to which they would aspire." Mariota is No. 3 in the NFL, 95th overall. That’s near James Earl Jones, Melissa McCarthy and Rodgers.

Breakthrough: "Indicates the degree to which people take notice of the celebrity when they appear on TV, film or print." Mariota is No. 1 in the NFL, 180th overall. Comparable to Arnold Palmer, Liam Neeson and Anne Hathaway.

Endorsement: "Reflects the degree to which people identify the celebrity as being an effective product spokesperson." Mariota is No. 4 in the NFL, 224th overall. Near Kelly Clarkson, Tony Dungy and Rory McIlroy. (Mariota has deals with Nike and Beats by Dre. The Beats commercial is a good watch.)

Influence: "Measures the degree to which people believe the celebrity is an influence in today’s world." Mariota is No. 6 in the NFL, 299th overall. Mariota ranks near Travis Pastrana, Neil Patrick Harris and Charlize Theron.

Trend-Setter: "Reflects opinion on the celebrity’s position with regards to trends in society." Mariota is No. 5 in the NFL, 434th overall. That’s on par with Paul Rudd, Olivia Wilde and Rob Gronkowski.

Trust: "Indicates the level of trust that the people place in the celebrity’s words and image." Mariota is No. 2 in the NFL, 247th overall. Comparable to Diane Sawyer, Mark Wahlberg and Michael Strahan.

The only people more excited by those numbers and names than Titans fans are the people who work in the team’s marketing arm and Mariota's agents.

Fan appeal and trust are not the top things an NFL team needs in its quarterback. But they are nice things to have, especially as a team hopes for patience from a fan base while it develops a player.

Maybe national endorsements beyond Nike and Beats will soon arrive to enhance Mariota's profile.

The danger?

We've all seen a young athlete in commercials when he has yet achieve much as a pro. Count me among those who are annoyed by it. For some consumers, it can hurt both player and product. (Robert Griffin III with Subway and Adidas comes to mind.)

If Mariota is in commercials while he’s struggling on the field, maybe it’ll dent the very likability that put him in the ad in the first place.

He’s a smart guy surrounded by smart people, and I suspect the strategy will be not to overexpose him too early.