The three - time NASCAR champion suffered a burst fracture of his L1 vertebra in a Jan. 31 all - terrain vehicle accident in the Southern California desert near the Arizona border .
The three - time NASCAR champion announced his pending retirement last September .
The three - time NASCAR champion , who announced his pending retirement last September , suffered a burst fracture of his L1 vertebra in a Jan. 31 all - terrain vehicle accident in the Southern California desert near the Arizona border .