Lael Stables' unbeaten Barbaro, winner of the Florida Derby (Grade I), worked five furlongs in 1:01.40 at Keeneland racecourse Sunday morning in his final preparation for the Kentucky Derby presented by Yum! Brands (gr. I).The move over a "fast" track under exercise rider Peter Brette was the third fastest of eight at the distance. The Michael Matz-trained son of Dynaformer went to the track around 7 a.m. (all times Eastern). "Everything went well," Matz said. Matz indicated that Barbaro would walk on Monday, then go to the track Tuesday and Wednesday before he ships by van to Churchill Downs on Thursday.Also working at Keeneland Sunday over the Polytrack surface on the training track was West Point Thoroughbreds' Flashy Bull, who was timed in :50 2/5 for a half-mile under exercise rider Desmond Farrell for trainer Kiaran McLaughlin.Two of trainer Todd Pletcher's Kentucky Derby contenders -- Aaron and Marie Jones' Sunriver and Starlight Stables, Saylor and Lucarelli's Keyed Entry -- worked over a "fast" track on Sunday at Churchill Downs. Sunriver, a brother to Pletcher's 2004 Kentucky Oaks (gr. I) winner Ashado and the third-place finisher in the Florida Derby (GI), took to the track shortly after the opening of training hours and worked six furlongs in company with Harlington, a 4-year-old graded stakes-winning stablemate. The son of Saint Ballado covered the distance in 1:14.20 - a clocking that was identical to that of his older workmate. The time was the best of just four works at the distance. Retired Hall of Fame jockey Angel Cordero, Jr. was in the saddle aboard Sunriver. "I thought he worked extremely well," said Pletcher. "He finished strong and galloped out well. He's training really well." Pletcher is keeping his fingers crossed the Sunriver will be able to make it into the Derby starting gate. At this point, he's on the bubble in terms of whether he has sufficient graded earnings to make the race if more than the maximum of 20 horses are entered. "I think yesterday in the Lexington, we had maybe one come out and one come in and we didn't lose any ground to where we were before. We'll see what happens here." Pletcher said Keyed Entry is now "definite" to be entered in the Kentucky Derby after he breezed five furlongs under Cordero just after the break for track renovation. The son of Honour and Glory, winner of the Hutcheson (GIII) and third in the Wood Memorial (GI), worked alone as he covered five furlongs in an official clocking of 1:00.80. The move ranked fourth among 48 at the distance. "I thought he worked dynamite," said Pletcher. "He was pretty relaxed, finished well and galloped out great. It looks like he handles the track very well. He's a good work horse and the main thing is I didn't want him to go too fast. But I liked the way he was very relaxed down the backside and had his ears pricked around the turn, and he finished without being asked at all. He galloped out very strongly, so he's dead-on." Patrick Valenzuela will ride Keyed Entry in the Kentucky Derby. Pletcher's other Derby contender, WinStar Farm's Bluegrass Cat, galloped 1 ¼-miles under exercise rider Luis Castillo. The winner of the Remsen is scheduled to work at Churchill Downs next Sunday. The injured John Velazquez had ridden both Bluegrass Cat and Sunriver before he went to the sidelines with injuries that will knock him out of action for the Kentucky Derby. Pletcher said he continues to search for a replacement rider for both horses. Garrett Gomez will take over duties as Pletcher's "first call" rider until Velazquez returns, but Gomez is already committed to ride Stonerside Stable's Bob and John in the Derby. In another development Sunday, McLaughlin said Like Now, second in Saturday's Coolmore Lexington Stakes (gr. II), would not contest the Derby and most likely be pointed toward the Preakness Stakes (gr. II).