NEW YORK (CNN/Money) - Jockeys in Saturday's running of the Kentucky Derby will be able to wear advertisements on their silks, a federal judge ruled Thursday.

Judge John Heyburn issued an injunction against rules of the Kentucky Horse Racing Authority that prohibited jockeys from wearing either advertising or a patch from The Jockey's Guild, an organization that represents their interests.

Jockey Jerry Baily wore an ad for Wrangler when he won the 2003 Belmont Stakes aboard Empire Maker. Baily was one of the plaintiffs in the case that Thursday allowed Kentucky Derby jockeys to also wear ads in that race.

Churchill Downs (CHDN: Research, Estimates), the track that hosts the Derby, said it did not have any problems with jockeys wearing advertising as long as it wasn't for a competitor of one of the race's sponsors, such as Visa. The jockeys' lawyer said he's confident his clients will be able to work within the track's guidelines.

"We're extremely pleased by the ruling. The jockeys got a much-needed win," said Ron Sheffer, the jockeys' attorney.

An estimated 11.9 million American watched the Derby, the premier horse racing event, on NBC in 2003.

According to court testimony, some jockeys could receive as much as $30,000 for wearing an ad just in the Derby.

One of the plaintiffs, Shane Sellers, who is riding Derby favorite The Cliff's Edge, testified he expected to be able to make even more than that on the Derby if he could sell an ad for all three Triple Crown races before the Derby started.

While jockeys get 10 percent of the prize money if their horse wins or 5 percent if the horse finishes second or third, most of the jockeys in the 20-horse field this Saturday will go home with very little money -- as little as $56 for the race, according to testimony in the case. Many have severe health problems due to efforts to keep their weight down or injuries from riding.

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A statement by Bill Street, the chairman of the authority, said while the judge's ruling had only opened the door to five jockeys who brought the suit wearing ads, the authority would allow any jockey in the state to wear ads while the ruling is in force. But it said it still wanted to work with the court on changes in the rules in the future.

"The horse's owner, who pays all bills, should be an active participant in the decision-making process on advertising worn by jockeys," said the statement. "In addition, the Authority recognizes that racing associations may also regulate advertising worn by jockeys."

The court ruling said all jockeys would be able to wear the guild patch. The judge said he will hold another hearing within 30 days to consider the ruling and could decide to modify it or even overturn it at that time.

"It's not a final victory," said Sheffer.

Jockeys who wore the Jockey's Guild patch in last year's race were fined $500. The Kentucky Horse Racing Authority was threatening to have jockeys who violated the advertising rule removed from the track, while some jockeys were threatening to boycott the race if they did not have a chance to wear advertising.

Several other states, including New York and California, already allow jockeys to wear advertisements.