Significant riding assignments were announced on Monday, with Daily Racing Form reporting that Ramon Dominguez has decided to stick with champion Hansen in Derby 138, and that Rafael Bejarano will ride El Padrino.

Dominguez was also the regular rider of Godolphin's Alpha, whose Derby jockey was yet to be finalized at last report.

Bejarano was temporarily left without a Derby mount after Secret Circle was sidelined by injury. He will be guiding the Todd Pletcher-trained El Padrino for the first time.

Irish-based jockey Colm O'Donoghue retains the mount aboard Daddy Long Legs, trainer Aidan O'Brien's wife Annemarie tweeted Monday. Daddy Long Legs is scheduled to ship from his Ballydoyle headquarters early next week.

Aside from the news about Dominguez riding Hansen, there was another Monday bulletin regarding the charismatic gray.

According to a press release issued on behalf of co-owner and namesake Dr. Kendall Hansen, the champion colt will be running in support of the Thoroughbred Racing Fan Association,

Dr. Hansen has offered to "donate 1 percent" of his "share of the winnings from the Kentucky Derby," ThoroFan Chairman Michael Amo said.

Established in 2008, the non-profit ThoroFan describes its mission "to retain and enrich existing fans, seek out and attract new fans and give each fan, regardless of involvement, a voice to the industry."

Amo said that the offer came from Dr. Hansen via e-mail.

"Dr. Hansen's offer and willingness to help build the racing fan base -- a major goal of ThoroFan -- is just the thing that is needed," Amo said. "Members of ThoroFan, especially the Kentucky Chapter, will be out in full force cheering for our newest member, Hansen."

Dr. Hansen has also designated 1 percent of the colt's Derby earnings for the equine charity New Vocations. As its name implies, New Vocations helps retired racehorses transition to new careers and homes.

According to Amo, Dr. Hansen added that he "can raise awareness through speaking up about the two charities Hansen will be running for in the Derby -- ThoroFan and New Vocations."