LOUISVILLE, Ky. – For a while there, Silver Rock was one of those mild disappointments. “He acted like he was a decent horse early but just couldn’t get his act together,” said trainer Mark Casse.But after four defeats to open his career, Silver Rock is on his way. He won a maiden race on the Gulfstream Park turf in late February, then followed that by winning as the favorite in a first-level allowance on the Keeneland turf on April 9. Both victories came since Casse equipped Silver Rock with blinkers.“Those last couple of races have been really big, especially since we put blinkers on him,” said Casse. “In his last, I thought the pace was so slow that we had no shot, but he was still able to rally.”Casse pointed out that the horse Silver Rock defeated, Screenplay, came back to win on the closing-day card at Keeneland “ and that’s always good to see.”Silver Rock, with Shaun Bridgmohan back to ride, will make his next start Tuesday, when Churchill Downs kicks off five straight days of Derby Week racing with a 10-race card that starts at 12:45 p.m. Eastern. Silver Rock is part of a big field in the richest race of the day, the ninth, a $53,500, second-level allowance at 1 1/16 miles on the turf.Silver Rock was assigned post 10, which would be the far outside post, assuming the race stays on grass. The only horse outside of him, Flying Pegasus, would start only in case the race is switched to the main track.Overall, the field for the Tuesday feature is a deep one. Among the other contenders is Mobilizer, a last-out winner for Roger Attfield, who ended Keeneland on a high note Friday when he sent out Musketier to win the Elkhorn for a second straight year, and Meezaan, an interesting Shadwell Farm import making his stateside debut for Dan Peitz.One of the two 3-year-olds in the field is Wilkinson, who was knocked off the Triple Crown trail when 10th in the Blue Grass Stakes. “We’re just looking to try something different with him,” trainer Neil Howard said of switching Wilkinson to turf.One other allowance (race 4) also is on tap for the only Tuesday card of the meet.