LOUISVILLE, Ky. (AP) - Michelle Nihei abandoned a promising career in medicine nine years ago and headed to the racetrack.

That gamble could pay off Friday when Nihei sends out Prince Will I Am, her first Breeders' Cup runner, in the $1 million Marathon.

Prince Will I Am, 4-1 on the morning line, will look to extend his winning streak to three in the 1 3/4 mile Marathon, the first of the 14 Breeders' Cup races over two days at Churchill Downs.

Nihei, 39 with a Ph.D. in neuroscience, was a member of the junior faculty at Johns Hopkins University in Baltimore when she decided to make a drastic career change.

``I reached a point where I needed to decide how much deeper I was going to commit to Hopkins,'' Nihei said. ``Some people were just going through the motions, waiting to retire so they could do what they really wanted. I didn't want to be that person.

``Sometimes it's not clear why something or someone is not making you happy, but you need to move on, otherwise you could live the rest of your life wishing you had done something else. I didn't want that to be me.''

So she headed to the track, working as an exercise rider.

``I was always a horse fanatic and stayed in contact with it, but it was scary,'' Nihei said.

She worked her way up to assistant for a number of trainers, including Todd Pletcher, before opening her own stable in 2007.

``Working for, and learning from Todd, is like going to Johns Hopkins,'' Nihei said.

She won her first race with Heartaches at Tampa Bay Downs on Jan. 6, 2008 and now has 20 horses in training. Prince Will I Am was her first Grade 1 winner, roaring from last to first in the 11-horse Jamaica Handicap last month at Belmont Park.

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A TALE OF TWO GRAYS: Informed Decision and Forever Together return to the Breeders' Cup on Friday in need of victories to salvage disappointing seasons.

The gray mares, both trained by Hall of Famer Jonathan Sheppard, are past Breeders' Cup winners. Informed Decision captured last year's Filly & Mare Sprint, while Forever Together won the 2008 Filly & Mare Turf and was third last year.

``They're the same, but things haven't transpired quite the same,'' Sheppard said. ``But to have to have two horses still running close to the top, the second year for one, the third for the other, is very rewarding.''

Informed Decision is the 7-2 second choice to defend her title in perhaps the most wide-open race on Breeders' Cup weekend. The seven-furlong Sprint attracted a field of 14 with Rightly So, the 3-1 morning-line favorite, drawing post No. 13.

Rightly So scored stakes wins in her last two races, including the Grade 1 Ballerina at Saratoga, but the front-runner might have difficulty clearing the lead from the outside post with several speedy fillies and mares starting to her inside.

Informed Decision raced close to the pace in last year's victory on the synthetic track at Santa Anita, which clinched the Eclipse Award as champion female sprinter. She also can rally from far back, coming from 11th to win the Presque Isle Downs Masters in September.

A winner of 14 of 21 career races, 5-year-old Informed Decision is just 3 for 7 this year.

Forever Together is 10-1 in the $2 million Filly & Mare Turf against Midday, last year's winner and the 6-5 morning line favorite. Forever Together is winless in five races this year with two seconds and two thirds.

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ON THE FENCE: The possibility of showers Thursday night and into Friday could keep Workforce in the $3 million Turf on Saturday.

The 3-year-old colt emerged as one of the world's leading grass stars this season with victories in the Epsom Derby in England and the Prix de l'Arc de Triomphe in France.

He is the 7-5 favorite in the Turf, if he runs. The Workforce camp is worried about the course at Churchill Downs, which is much harder than any Workforce has raced or trained on in Europe. They would rather scratch than run on grass that might jar their horse.

``It's firmer than we'd like and there has not been enough rain,'' trainer Michael Stoute said. ``We'll monitor it each day.''

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INDIAN GRACEY OUT: Indian Gracey was scratched Thursday from the $2 million Juvenile Fillies with a sore right front foot.

Owner-trainer Jerry Hollendorfer wasn't happy with the way she left the track a day earlier.

``She has a hot right front foot, so we're not running,'' Hollendorfer said. ``I'd rather know now than in the race. She's talented, so she'll get other chances. But we're going to do the right thing by her and not run this time.''

Indian Gracey had drawn the rail in a field now reduced to 12. She is 1-2-1 in four starts, finishing third most recently in the Grade 1 Oak Leaf Stakes at Hollywood Park.

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ON CALL: The American Association of Equine Practitioners' On Call program will be in effect this weekend at the Breeders' Cup.

Leading veterinarians will be on hand to provide health updates on the horses competing at Churchill Downs. Equine surgeons Larry Bramlage and Wayne McIlwraith head the effort.

Bramlage is a partner at Rood and Riddle Equine Hospital in Lexington, Ky. McIlwraith is a professor of surgery and director of the Orthopaedic Research Center at Colorado State.

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BRING THE MITTENS: Fans heading to the Breeders' Cup will need to bundle up.

The high temperature Friday is expected to reach the upper 40s before dropping from there for the first Breeders' Cup card held under the lights. There is also a chance of showers.

It should be slightly warmer and drier on Saturday with sunny skies.

Those trying to fend off the rain and chill have limited options after Churchill Downs issued a list of prohibited items that includes umbrellas, blankets, tarps, backpacks and alcoholic drinks. Fans can bring food and box lunches packed in clear plastic containers.