Jockey Mark Johnston has a big ride lined up for today, all the way to California.

Johnston, 20, will eschew three days of mounts at Laurel to attend Saturday's Eclipse Awards in San Francisco. He's the favorite among three finalists for the apprentice championship of 1990, but all the trip guarantees is a hefty bill.

Other than a ticket to the awards presentation, Johnston and the other Eclipse candidates receive no other perks. They must pay for travel expenses and lodging, and guests' tickets to the awards ceremony must be purchased. By inviting his mother, sister and a friend, Johnston figures this a $3,000 excursion.

"I don't want to go out there and not get it," he said. "But if I do, the cost'll be every bit worth it."

Johnston led the country's apprentice jockeys in wins and purses last year, even though his apprenticeship expired in July. Paul Toscano of New York and Vann Belvoir of Washington are the only ones who can prevent him from becoming the seventh apprentice champion from Maryland since Eclipse Awards first were given in 1971. He also would become the fourth in five years, following Allen Stacy (1986), Kent Desormeaux (1987) and Mike Luzzi (1989).

The Eclipse Award winners will be announced on ABC late Saturday afternoon following its telecast of the Donn Handicap.

Johnston has become a journeyman without notable slippage in production, mostly because he remains the No. 1 choice of King Leatherbury, Maryland's winningest trainer. Johnston piloted the Leatherbury-sent Double Artemis to victory in yesterday's $25,000 allowance feature at Laurel and earlier brought Mt. Airy Slew to a tenuous win in a $20,000 claimer.

He has had at least one winner each of the last 11 programs and ranks sixth for the meet with 76 victories. Luzzi has a mighty hold on the Laurel title with a 119-96 advantage over Edgar Prado.

"My goal is to get a leading rider title as a journeyman," Johnston said.

"When you do it with the bug, you have an advantage -- a five-pound advantage. I think it'd mean a lot more if I was on even terms with everybody."

At 5 feet 8, he said, weight control remains no great strain. He said he tacks 112 pounds with one or two visits a week to the steamroom.

Announcer Announcement

Dave Rodman of Louisiana Downs will become full-time announcer when the Pimlico meet opens March 14, it was announced yesterday.

Rodman, 32, has been calling races for 10 years, six at Louisiana Downs. He will succeed John Curran, who has described Laurel's races since Jehan Malherbe returned to South Africa late in December. Curran resumes as Delaware Park's announcer next month.

Since Dick Woolley departed in September 1988, Maryland's thoroughbred tracks have gone through six announcers: Robin Burns, Ray Haight, Trevor Denman, Milo Perrins, Malherbe and Curran. In addition, Doug Vair, Jack Salter and Ryan Kelly have made minor appearances. . . .

Post positions were drawn for Saturday's $500,000 Donn Handicap, the first of 10 races that constitute the American Championship Racing Series. Rhythm, the early favorite in a 12-horse lineup, got Post 3 for the 1 1/8-mile race at Gulfstream Park and faces the likes of Killer Diller, Yonder, Secret Hello and Mercedes Won.

The ACRS will award $750,000 to the horse who performs best through the 10-race program, and a total of $1.5 million overall. The series, which includes the Pimlico Special, finishes with the Woodward Stakes on Sept. 15. . . .

Clarence "Jo Jo" Ladner has begun exercising horses and could resume racing by the end of next week. The veteran jockey has been sidelined 3 1/2 months after having a steel plate removed from his right arm and another operation on his damaged right eye. . . .

John Faltynski has taken the book of apprentice Tim Peterson, who rode yesterday's longest-priced winner in Mutant Ninja Sandy, $88.80.