By Bruce Martin SportsTicker Contributing Editor

SPARTA, Kentucky (Ticker) -- Actor Jason Priestley suffered serious head injuries Sunday in a crash during a practice session for an Infiniti Pro Series raceat Kentucky Speedway, but is in stable condition.

Priestley, the former star of "Beverly Hills 90210," is a competitor in the developmental series for the Indy Racing League.

During the practice session, Priestley approached a portion of the track where oil dry had been laid down after Ronnie Johncox's car leaked fluid on the course. While other cars were able to avoid it, Priestley apparently did not know the slick substance was on the course and ran right through it.

A rooster-tail of dust came from the back of Priestley's car as it lost traction. His Dallara/Infiniti hit the outside wall in the second turn, heavily damaging it, then veered across the course and smacked into an inside retaining wall.

Priestley was airlifted to the University of Kentucky Hospital in Lexington, about 75 miles away. According to Dr. Henry Bock, the IRL's director of medical affairs, Priestley suffered serious head injuries, but is responding to commands.

The crash occurred at 8:42 a.m. EDT.

According to two-time Indianapolis 500 winner Arie Luyendyk, who was spotting for his son, Arie Luyendyk Jr., Priestley "turned right into the wall, and his first impact was basically head-on."

In three Infiniti Pro Series starts, Priestley's best finish was third at Kansas Speedway. He was the second-fastest qualifier for Sunday's race during Saturday's qualifications, with a lap at 179.064 miles per hour. He ran a fast lap of 178.122 mph in eight laps of practice Sunday morning.

The 32-year-old Priestley began racing in the California Rally Series in 1991 and competed in the SCCA Pro Rally Series from 1992-95. He drove in the IMSA Firehawk Series and Magna Enduro Series from 1995-99, earning his first victory at Mid Ohio Sports Car Course in 1998. In 1998-99, he also drove in the Sportscar GTS1 Series.

A native of British Columbia, Priestley is no stranger to accident. He wrecked his Porsche in December 1999, later pleading no contest to a misdemeanor DUI charge, and crashed a powerboat during a race in Miami in April.