Updated

Joe Gibbs Racing revealed on Thursday that Mark Martin will drive the No. 11 Toyota in the Sprint Cup Series while Denny Hamlin recovers from his back injury.

Hamlin is expected to miss the next six weeks of races after he sustained a compression fracture in his lower back during his last-lap accident in the Sprint Cup race last Sunday at Auto Club Speedway in Fontana, Calif.

Martin will make his first start for the team on April 7 at Martinsville Speedway. The series takes its first break of the season this coming weekend. Martin is running a 25-race schedule for Michael Waltrip Racing this year, driving the No. 55 Toyota. The 54-year-old driver was not scheduled to compete at Martinsville, as Brian Vickers was slated to be behind the wheel of the No. 55 at that half-mile racetrack.

"We've been real fortunate to have never been in this situation with the need to find someone to fill in for an injured driver," JGR team president J.D. Gibbs said in a statement. "A lot goes into a decision like this, but we are really pleased to have someone of the character and caliber of Mark Martin to fill in while Denny is out. Obviously, we're not exactly sure how long that is going to take, but Mark's career speaks for itself, and our team knows it will have the opportunity to compete for a win every week."

Martin drove for JGR in a Nationwide Series race in March 2012 at Las Vegas, where he finished second.

"I'm happy to have this opportunity to help out JGR, (team sponsor) FedEx and Denny," Martin said. "Hopefully, I can keep those guys up front and compete for wins while Denny heals up."

Martin has scored two victories, 25 top-10 finishes and two poles in 48 career starts at Martinsville.

"I just hate not being able to be in the car right now, but I really appreciate Mark being able to fill in for me," Hamlin said. "Like everyone in NASCAR, I have a tremendous amount of respect for Mark, and I know he will keep that FedEx Camry up front until I get back behind the wheel."

Hamlin's crash at Fontana occurred when he was battling his former JGR teammate, Joey Logano, for the lead on the final lap. Both drivers made contact and spun. Hamlin skidded down the track and then slammed hard into the inside retaining wall. His car came up off of the ground and spun around after it ricocheted off of the wall.

Hamlin climbed out of his car under his own power but then laid down on the track, as safety personnel quickly tended to him. Shortly after, he was airlifted to nearby Loma Linda University Medical Center. Hamlin remained hospitalized until late Monday. He was wearing a back brace when he left the hospital.

On Tuesday, Hamlin was evaluated by Dr. Jerry Petty of Carolina Neurosurgery and Spine Associates in North Carolina. Petty determined that Hamlin wouldn't need surgery but would need time to properly heal, which is estimated around six weeks time.

Texas (April 13), Kansas (April 21), Richmond (April 27) and Talladega (May 5) are those races that follow Martinsville.

Hamlin made the Chase for the Sprint Cup championship for the seventh straight season in 2012, every year he has been a full-time competitor in the series. He won rookie-of-the-year honors in the series in 2006. Hamlin also has 264 consecutive Sprint Cup starts. He is currently 10th in the point standings.