Castellano is Chad Brown's go to rider, not Pletcher's. I looked up last year's Derby day sheets. At the time, the TG data listed 606 mounts for Castellano for Pletcher out of 10,553 starts, which means Castellano was aboard for 5.74% of Pletcher's starters. Meanwhile Javier had 498 mounts for Brown out of his 1,726 starters, a much greater 28.69% of Brown's horses.

Unless it comes down to where there is a clear difference between the horses, the jockey and his agent are going with the guy who brought him there and is more likely to do so again. Few can say that either General A Rod or Tapiture has a really good chance to win this race.