Trainer Dick Mandella was looking for a big work from Action This Day Thursday morning to convince him last year's champion 2-year-old could rebound from two poor efforts. After the colt's six-furlong work in company with 2-year-old filly champ Halfbridled, Mandella had his answer.With Pat Day aboard, Action This Day and Halfbridled tore around a deep Churchill Down oval in 1:12 2/5, with Action This Day galloping out a strong seven furlongs in 1:25 4/5.Mandella had hoped he had unlocked the mystery of Action This Day's dismal performances in the San Felipe (gr. II) and Blue Grass Stakes (gr. I) when the colt came out of the Blue Grass stiff behind. He had a rough trip in the San Felipe and was grabbed from behind by a loose horse, which may have caused the stiffness in his back. After a regimen of chiropractic work and message therapy, Action This Day responded and seemed to be back to his old self. But Mandella realized he wouldn't know for sure until the colt worked and came out of it in good physical shape.Subsequently, Halfbridled also needed a good work following two defeats this year, and Mandella decided to work them in company. A steady rain began to fall during the renovation break, turning an already wet track even wetter.Mandella gave Day a leg up on Action This Day and told him, "Pick it up right before the quarter pole, and then just a nice steady finish. Let him gallop out a strong eighth." Action this Day needed that extra stiff gallop-out more than Halfbridled.Moments before the pair worked, Bob Baffert sent Preachinatthebar five furlongs. After clocking the son of Silver Charm an opening quarter in :25 3/5, Baffert knew the work was not going to be was he was looking for. "I should have worked him in company," Baffert said. He caught the colt in 1:01 3/5, but his usual enthusiasm following a typical Derby work was missing this time.Shortly after, Action This Day and Halfbridled broke off at the six-furlong pole and eyeballed each other down the backstretch and around the far turn, with Action This Day down on the inside, being he was to gallop out stronger than the filly. Turning for home, the two champs were really motoring, cutting the corner beautifully. Both horses were allowed to do everything pretty much on their own down the stretch. Action This Day is a good-sized colt, with powerful quarters, but still seemed dwarfed by the towering Halfbridled, who stuck her head in front inside the sixteenth pole. But Action This Day dug in and came back at her, the two hitting the wire dead-even. Action This Day eased clear in the gallop-out, as instructed, but Halfbridled remained just off his flank.When another of Baffert's horses worked in 1:01 and change, he realized just how quick Mandella's two horses had gone, "Man, they were smokin,' Baffert said. "This track is pretty slow."Now, all Mandella has to do is wait until tomorrow to see how they come out of the work, paying particular attention to how Action This Day's back held up. If there is no sign of stiffness, he's on his way to the Derby.When Baffert got back to the barn, he began having second thoughts about subjecting Preachinatthebar to the rigors of the Derby. Feeling the colt wasn't up to the task following this kind of work, he contacted owner Mike Pegram, and the two decided not to take the chance of ruining the horse, and withdrew him from the Derby.Earlier in the morning, Kristin Mulhall prepared Imperialism for his six-furlong work, as soft, soothing music trickled out from a radio outside his stall. By 5 o'clock the colt was already tacked up and ready to go. After putting on the final touches, Mulhall gave him a gentle pat and planted a kiss on his neck.Owner Steve Taub then came jogging toward the barn, having finished his daily constitutional, running from his hotel to the track. He carried an orange in each hand, and gave one to Mulhall, as a student would present an apple to the teacher. "Hello, there, sunshine," he said to Mulhall (or was it to the horse?). When Imperialism walked out of his stall, he stopped and stretched his hind leg, extending it straight out. Mulhall said it's something he's been doing since he arrived at her barn in January.With Mulhall aboard, as usual, Imperialism broke off at the six-furlong pole, and as he passed under the floodlights by the old clocker's stand, another horse, working five furlongs, dropped in in front of him. Mulhall eased Imperialism off the rail. She had no idea that the other horse was Azeri, who was beginning her five-furlong drill in :59 3/5. Imperialism went about his business, and basically appeared to doing something between a work and a two-minute lick. He completed the six furlongs in 1:17 2/5. Knowing he was going slow, Mulhall let Imperialism gallop out farther than usual, and didn't pull him up until he had gone the length of the backstretch, past the half-mile pole.Taub, who is relishing in every minute of the Derby experience, ran to catch up to the horse, stopping quickly in the media center, where he grabbed three donuts, then offered them to Todd Pletcher, who was coming off the track just ahead of Imperialism (for the record, Pletcher cordially declined the offering).When Mulhall came off the track, she told Taub she thought he had gone in about 1:17, and pretty much hit it right on the head. "I'd rather see him go in 1:17 than 1:12," Taub said."This was his normal self," Mulhall said, "He's pretty fit."Florida Derby (gr. I) winner Friends Lake went out for his first tour of Churchill Downs at around 8:40 and looked super, galloping strongly with his head down and into the bit. Horses often can be distracted by all the activity and new surroundings when they come to Churchill, but Friends Lake went around like he's been there his whole life.Although he appears at first glance to be on the light side, trainer John Kimmel said he's gained 30-40 pounds since the Florida Derby. The son of A.P. Indy is a long-backed colt and one would not expect a stayer type like him to carry much flesh. He looks dead-fit, and is as stubborn as ever. If you remember the ordeal of trying to load him in the gate in the Florida Derby, it wasn't much different this morning trying to get him back in his stall. At home, he's used to rolling around in the sand pen before going back in. This morning, after grazing for a while, he eyed Wayne Lukas' sand pen about 100 yards away. As if reminded of his daily routine, he started pawing at the ground, trying to get down and roll. When he wasn't allowed to, he began pawing more vigorously, splashing the water from the wet grass, as a little kid would do who doesn't get his way. Finally, he was brought back to the barn, and it took quite a while for a patient Kimmel to finally coax him back in his stall. This colt is quite a character, reminiscent of Fusaichi Pegasus. Kimmel said he's going to ask Lukas for permission to use the sand pen, which was a lifesaver for Fusaichi Pegasus' trainer Neil Drysdale before the 2000 Derby. Kimmel said Friends Lake will work five furlongs on Saturday.Nick Zito took it easy with The Cliff's Edge this morning after his :59 3/5 work on Monday. The big son of Gulch pretty much side-stepped his way around the track, bowing his neck and looking to do more. Stablemate Birdstone had another strong, smooth gallop, and couldn't be doing any better.Earlier, Wimbledon was out for his gallop, and it's obvious watching him that this big, powerful gray is still in his raw stage, as he attempts to get his legs moving in unison with his body. His lead change is quite noticeable for a gallop, but he does generate a tremendous amount of power, suggesting he's going to be something to see once he fully matures. Baffert can only hope that maturity surfaces on May 1.