Police spokesman Lt. Doug Perry said Thursday that personnel at the Alpine Motel discovered the Mechanicsville native in his room at about 11 a.m. Wednesday.
Investigators did not speculate on the cause of death, but officials said there doesn't appear to be anything unusual or suspicious at the scene.
The 31-year-old was suspended from NASCAR indefinitely in 2006 because he refused to submit to a random drug test following the Busch Series race at Richmond International Raceway.
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Grubb was previously suspended in March 2004 for failing a drug test. But he agreed to random testing as part of his reinstatement.
Grubb's career began with NASCAR's lower-tier series in 1997.