Dale Earnhardt Jr. returned to competition on Friday at Martinsville Speedway for the first time since missing the last two Sprint Cup Series races.

Earnhardt Jr. was forced to sit out Charlotte and Kansas after being diagnosed with a concussion days after he was involved in a multi-car wreck on the final lap of the Oct. 7 race at Talladega. The driver of the No. 88 Hendrick Motorsports Chevrolet also sustained a concussion during a crash while participating in the Aug. 29 Goodyear tire test at Kansas, which had recently been repaved.

During Friday's lone Sprint Cup practice session at Martinsville, the site of the seventh race in the Chase for the Sprint Cup championship, Earnhardt Jr. posted the second quickest lap at 97.488 mph. He drove a total of 31 laps around the 0.526-mile racetrack. Brian Vickers, who is driving the No. 55 Michael Waltrip Racing Toyota, topped the practice charts with a lap at 97.679 mph.

Prior to practice, Earnhardt Jr. met with the media to discuss his concussion as well as taking the last two weeks off. His last public comments came on Oct. 11, which was two days after Dr. Jerry Petty, a neurosurgeon, examined him in Charlotte.

"It's just been a lot of time off and a lot of time on my hands," Earnhardt Jr. said. "I've been exercising and doing what the doctors told me to do and feeling better every day. I've been going through the process. You just got to be patient and let things happen.

"I've learned a ton about what I went through. I feel like I'm a lot smarter and a lot more prepared and understand the situation a lot better now than beforehand. It's been a good experience. It's something I would have rather not gone through, but I learned a lot from it, and it's been good for me. I'm just excited to be back to work and get back in the car."

Earnhardt Jr. is NASCAR's most popular driver and one of the 12 drivers in this year's Chase field. After finishing 20th at Talladega, Earnhardt Jr. trailed leader Brad Keselowski by 51 points. He is now 122 points behind Keselowski.

"I felt like I could race at Kansas, for sure, and probably ran at Charlotte with no problem," he said. "I felt kind of foolish sitting at home and feeling okay and not being in the car. It feels really unnatural."

There had been speculation that Earnhardt Jr. might miss the rest of the season after the disclosure of his concussion. But Earnhardt Jr. said he wanted to return to racing as soon as he was medically cleared.

"In the decision to get out of the car in the first place, I just wanted the doctors to make that decision instead of me," he admitted. "If I could race, I wanted to be at the racetrack. It's what I love to do. If the doctors felt I was healthy enough to do that, I wanted to be doing it."

Earlier this week, Earnhardt Jr. ran 123 laps in a Sprint Cup car during a test session monitored by Petty at the half-mile Gresham Motorsports Park in Jefferson, Ga. Petty then cleared him the following morning after a final neuropsychological evaluation.

Earnhardt Jr. was also evaluated by Dr. Micky Collins, director of the University of Pittsburgh Medical Center Sports Medicine Concussion Program, last week.

Regan Smith substituted for Earnhardt Jr. in the No. 88 car at Charlotte and Kansas.

"It was really hard to see your car out there running around and turning laps without you in it, so that was difficult," Earnhardt Jr. said.

Smith finished 38th at Charlotte due to engine failure and then seventh at Kansas.

On Wednesday, Earnhardt Jr's Nationwide Series team, JR Motorsports, signed Smith to drive the No. 5 Chevrolet full-time during 2013 Nationwide season. His signing with JRM came one month after he was relieved of his driving duties in the No. 78 Chevrolet for Furniture Row Racing in Sprint Cup. To prepare for the upcoming season with Furniture Row, Kurt Busch took over as driver of the No. 78, starting at Charlotte.

Smith was originally scheduled to replace Busch in the No. 51 Chevrolet for Phoenix Racing but was called upon by team owner Rick Hendrick to drive the 88 car.

"Regan did a really good job for the team," Earnhardt Jr. said. "I told him that I was worried about the momentum that we had built up as a team, and he maintained that. I feel like we didn't miss a beat, and I can get back in the car as if nothing has really changed. All of that couldn't have gone better."