The Maryland Racing Commission, acting on a recommendation by Laurel Race Course stewards, fined apprentice jockey Mark Johnston $1,000 yesterday for failing to ride out One Third in Tuesday's ninth race.

It is believed one of the largest fines issued a jockey in Maryland racing history.

Johnston, who leads the country's jockeys in victories with 240 this year, was cited after he failed to ride front-running One Third aggressively through most of the stretch in the $19,000 allowance race. In anticipating an easy victory, Johnston restrained the 11-10 favorite in the lane after glancing back at his closest pursuers, only to be surprised by a late charge from McKilts, who won by a nose.

Johnston's complacency cost the filly's owner, Double Paces Stable, $7,220 in purse money and affected win, exacta and pick three wagering.

After the race, he said he "screwed up" by misjudging One Third's lead and underestimating McKilts's closing kick. Once McKilts rallied outside of One Third, Johnston began pushing his filly. But with only a few strides remaining, One Third couldn't catch McKilts.

After reviewing films of the race with Johnston yesterday morning, the stewards agreed to fine Johnston but not suspend him. Because they are not empowered to assess fines in excess of $500, commission approval was required.

Ken Schertle, the commission's executive secretary, reported by late afternoon that a majority of the nine-member commission endorsed the recommended penalty.

Chief steward Clinton Pitts Jr. said the stewards did not suspend Johnston because the jockey did not deliberately lose the race.

"There wasn't any chicanery or criminal intent on his part," Pitts said. "He just got caught sleeping. That's going to happen to anybody who rides long enough. We felt this was the most equitable way to get his attention."

Johnston, 19, called the ruling "fair" and was relieved not to have been suspended at a critical time in his career. Because Johnston remains an apprentice only until Wednesday, a suspension could have hindered his transition to journeyman status, in which his mounts will no longer receive a five-pound benefit.

"It was a mistake," Johnston said of the overconfident ride. "It cost the owner and it cost the public. The person responsible deserves to get fined."

With four days left in Laurel's summer session, Johnston is approaching his second consecutive meet title. He has 37 victories at Laurel, five more than second-place Joe Rocco.

Mango Named GM

Jim Mango, vice president of operations of Laurel and Pimlico, has been named general manager of the tracks as part of corporate restructing within the tracks, president Joe De Francis announced.

The move was prompted after co-owners Tom and Bob Manfuso withdrew from day-to-day operations in May. Mango will remain the tracks's principal troubleshooter, and in assuming some of Tom Manfuso's responsibilities also will oversee maintenance and improvements to Laurel, Pimlico and the Bowie Training Center.

To assist Mango, De Francis named Terence Casey to the new position of assistant general manager, effective Aug. 3. Casey recently resigned as general manager of The Galleria Shopping Center at Tysons Corner.