After a self-proclaimed successful rookie year, the team behind the “Gridiron Grunts” app — which lets NFL players and fans talk to each other via recorded voice messages — is beefing up for its second season with plans to add picture- and video-sharing capabilities.

According to ex-NFL lineman Jeb Terry Jr., who is co-founder and CEO of Grunts parent company Gridion Ventures Inc., adding picutre and video sharing is just another way of adding value to an app that was “built just to talk about football.” If you’re not familiar with the Grunts app, a “Grunt” is a short (less than 45 seconds) audio message that can be recorded from a phone to the app.

The big attraction are “Grunts” left by NFL players, though fans who download the app can send Grunts to players, as well as “Grunt” to other fans. Fans pay 99 cents per month to listen to grunts of a specific player, or $4.99 a month to listen to all pro grunts. Fan-to-fan grunting is free, and the app is available for both iPhone and Android devices.

The “Grunt” label comes from the way football players talk on the field, a language Terry and his co-founder Ryan Nece used often as teammates on the Tampa Bay Buccaneers. “We used to knock heads in practice and then go out and have steaks afterward,” said Nece, who was a linebacker for Tampa from 2002-07.

After leaving the NFL following the 2008 season Terry went back to school to get an MBA, and then hit his old training partner with an idea for bringing fan-player interaction to a wider audience.

“It’s all about giving the fans the ability to engage with a player at their convenience,” said Nece. Terry said the pick-up-a-phone-and-grunt also makes it easy for players to participate.

“It’s convenient and easy to do, and gives players another way to control their own brand,” Terry said. “And fans can listen to a grunt at their leisure. You can’t always listen to radio talk shows when they are on the air.” The Grunts app can also deliver alerts to a fan’s phone when there is a new grunt to listen to.

Nece added that Grunts is a way for players who aren’t Tom Brady or Aaron Rodgers to get some air time.

“There are a lot of players like we were, with shares of the limelight that were pretty small,” Nece said. “You could be a big fan of a certain player but never hear from him on ESPN. Now everyone can develop their own personality.”

According to Terry the Grunts app kicked off the season with just 15 pros participating, but ended with almost 80 players at the end of the season. One grunter who Terry really liked was Green Bay Packers breakout star Randall Cobb, who scored on both a kickoff return and a punt return last year.

“After that first game when he scored on the kickoff return he was very engaging, with some great postgame grunts,” Terry said. “He was perfectly candid and very excited for the fans.”

The Grunts team said it attracted 20,000 paying customers during the first year, a “beta” season total that Terry is happy with. For this year, after adding photo and video sharing later this spring, the Grunts team is still considering where to expand next, with perhaps a Grunt website and other sports on the drawing board. But first and foremost, the Grunt app will remain simple and powerful, like a blitz: A place to talk and listen football.

“Twitter is fun but tweets might be from friends or associates [of an athlete], so you never know,” Terry said. “We built our app to talk about football, and not about shopping or going to the club. We just wanted to erase the clutter and bring fans content that’s strictly from the players.”