DAYTONA BEACH, FL - FEBRUARY 23: Jimmie Johnson, driver of the #48 Lowe's Chevrolet, and Dale Earnhardt Jr., driver of the #88 Nationwide Chevrolet, talk prior to the Monster Energy NASCAR Cup Series Can-Am Duel 2 at Daytona International Speedway on February 23, 2017 in Daytona Beach, Florida. (Photo by Chris Graythen/Getty Images)

Dale Earnhardt addresses whether his concussion is linked to his poor performance

Dale Earnhardt Jr. is well aware that his performance this year -- his last on the track -- has been sub-par. He's on the outside looking in on the playoffs, sitting 22nd in the standings. He needs a win in one of the last three NASCAR regular season races in order to qualify.

He's also been subject of some harsh criticism when Kevin Harvick criticized his performance and said he stunted NASCAR's growth.

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It's reasonable to wonder whether the concussion Earnhardt suffered last season -- one that cost him the final 18 races of the season and resulted in a lengthy and difficult recovery -- is the reason for his performance.

Earnhardt Jr., in remarks to, shot that down, when he said:

There are a lot of things that play a role in being competitive. I think that I'm healthy and I'm happy and thrilled that I'm healthy. I still think I can drive a race car, but there is really no excuse for us not performing well or meeting expectations. There is no excuse for missing a lot of races. Kyle (Busch) missed a lot of races with his injuries (in 2015) and came back and was successful right out of the gate.

Earnhardt Jr. is hanging it up after this season to go into broadcasting.

Earnhardt told ForTheWin that every since he suffered a concussion that cost him the second half of the 2016 season, he wonders whether he'll get another.

"You can't completely block things like that out of your mind," he said.

Earnhardt was in a crash at the Michigan Motor Speedway in June of 2016, and that collision is believed to  be the start of his symptoms and his long road back. His battle back has been well chronicled. He said he didn't care about racing, only about getting better; he was scared to death from blurry vision and thought his career was over.

Now, at 42, he's entering his final season on the track and transitioning into the broadcast booth. Still, with the specter  of retirement near, the concussion worries are ever prevalent.

"If you're a football player and you blow out your knee or tear your ACL or something, you know what that felt like, you know what the rehab was like, how hard that is to get back. So you can claim it's out of your mind or you don't think about it, but it is. It's in the back of your mind all the time. Having that experience is a memory that you can't escape."

Earnhardt Jr. will drive his No. 88 Chevrolet Sunday at Michigan International Speedway, looking for his third career win on the track.