Dale Earnhardt Jr. will have the National Guard on his car for 20 races in 2013, but what company will sponsor the other 16 events?

That question remains unclear as of Friday, and Earnhardt Jr. said current sponsor Diet Mountain Dew is "going to back off a little bit" next season.

"That makes it a bit of a challenge to fill that small of a gap," Earnhardt Jr. told reporters at Chicagoland Speedway. "If It were a bit larger gap, it would be easier to fill."

So is there a chance Earnhardt Jr. might have some unsponsored races for next season? That remains unlikely for NASCAR's most popular driver, who said it's a matter of getting companies to share their space. With Diet Dew still wanting some races, Earnhardt Jr. might have three primary sponsors in 2013.

"Every sponsor on the car wants to be the top guy," he said. "It's a bit hard to have a top guy when you are trying to work with multiple sponsors. It's just a little bit of a balancing act."

Hendrick Motorsports has "a lot of irons in the fire," he said, and is just deciding which company would be a good fit for the 88 car.

"We just got to kind of decide which one is going to work out, which one we want to work with," he said.