Several key riding assignments have been confirmed for the 139th running of the Kentucky Derby on May 4.

John Velazquez will stick with Wood Memorial winner and likely Kentucky Derby favorite Verrazano, agent Angel Cordero Jr. reported on Wednesday. Velazquez has guided the Todd Pletcher-trained Verrazano to victories in all four career starts but faced a difficult decision due to the fact that he was also the regular rider for Florida Derby winner Orb, another leading Kentucky Derby contender.

Velazquez is currently sidelined after sustaining rib and wrist injuries in a spill at Aqueduct last Sunday, but is expected to resume riding May 1.

As a result of Velazquez's decision, Orb's connections quickly locked up the services of Joel Rosario, who will be re-united with the colt in the Run for the Roses. Rosario was up in Orb's first five starts, including a maiden win at Aqueduct in late November and an optional claiming win at Gulfstream Park on January 26, before surrendering the mount to Velazquez in the February 23 Fountain of Youth. Orb will bring a four-race winning streak into the Kentucky Derby for trainer Shug McGaughey.

On Thursday, Javier Castellano committed to ride Wood Memorial runner-up Normandy Invasion over Louisiana Derby hero Revolutionary. Castellano rode the Chad Brown-trained Normandy Invasion for the first time last Saturday and replaced the injured Ramon Dominguez on Revolutionary earlier this season for Pletcher.

Pletcher said they would wait until after this weekend's races to announce a jockey for Revolutionary in the Kentucky Derby.

"It was a difficult decision with Todd & Chad being our two biggest supporters, but we have chosen to ride Normandy Invasion in the Ky Derby," tweeted Matt Muzikar, Castellano's agent. "We appreciate & respect Revolutionary, (owner) Kenny Trout, Todd Pletcher, Elliott Walden & all of Winstar Farm. We wish them only the best!"

Garrett Gomez has also secured the Derby mount on Gotham winner and Wood Memorial third-placer Vyjack. The once-beaten gelding had been ridden by Rosario in his last two starts.