When Marco Castaneda broke his wrist in a fall last week, John Ottaviano felt it. "This really hurts," said the jockey's agent. "We've got some big races coming up."

Castaneda's scheduled mounts finished first in both stakes races last weekend at Laurel (although one was disqualified), a potential $7,800 swept away. It seems further torment awaits him, with Valay Maid's forceful presence in today's $75,000 Pearl Necklace Stakes on the turf at Laurel.

On her way to becoming the leading Maryland-bred 3-year-old filly of 1990, Valay Maid has thrived under diverse conditions. She's won races at five distances from six furlongs to 1 1/16 miles, on tracks wet and dry, and her latest conquest -- the Hilltop Stakes -- came in her first attempt on turf.

Now comes another wrinkle. Castaneda's injury means the Carnivalay filly will have a new rider for the first time in her last eight trips, trainer Carlos Garcia having chosen Chris DeCarlo for the job. DeCarlo was the jockey who went down with his mount in traffic last Saturday at Laurel in the spill that injured Castaneda.

Valay Maid has come from midpack in her last two stakes victories, but the lack of speed among her five rivals suggests she'll be closer to the pace today, if not setting it.

She'll start the grassy 1 1/16 miles from Post 2, with two of her Hilltop chasers to the outside. Baltic Chill, the Woody Stephens-trained filly she beat by three lengths, will have Post 3 and her first race with Lasix; Mymet, who rallied to finish within a length of Valay Maid, will break from the outside.

Winthrop Arms, who won a stakes race on Rockingham Park turf, is considered the other viable threat in a field lacking depth. Aside from Valay Maid, none of the Maryland-breds has earned as much as $50,000. . . .

Kelly Castaneda, Marco's younger brother, rode at Laurel yesterday after shaking off the effects of Thursday's spill. He took his only mount, Edieweet (13 to 1), to a second-place finish in the fifth race.