ELMONT, N.Y. &ndash; Activity has picked up in the muddled 3-year-old division, with several notable names putting in recent workouts and one high-profile colt returning to the racetrack as the push toward defining a champion is about to begin in earnest.\r\nPreakness winner Shackleford breezed four furlongs in 48.40 seconds Sunday morning at Churchill Downs, his first official workout since running fifth in the Belmont Stakes on June 11. Shackleford is preparing for the $1 million Haskell Invitational at Monmouth Park on July 31, a race that last year&rsquo;s Preakness winner Lookin At Lucky won en route to 3-year-old championship honors. The Haskell and the $500,000 Jim Dandy at Saratoga on July 30 are stepping-stones to the $1 million Travers at Saratoga on Aug. 27. All three races will be important in determining the 3-year-old champion.\r\n&ldquo;It&rsquo;s wide open,&rdquo; trainer Dale Romans said of the 3-year-old division. &ldquo;Someone&rsquo;s got to jump up and run big in the Haskell or Travers or both.&rdquo;\r\nRomans said Shackleford would have two more works at Churchill before being shipped to Monmouth.\r\nOn Monday afternoon, Uncle Mo, the defending 2-year-old champion who was sidelined from the Triple Crown due to what was diagnosed as a rare liver disease, arrived in Saratoga, where his connections hope to bring him back in the Grade 1 King&rsquo;s Bishop at seven furlongs on the Travers undercard. Though Uncle Mo has only an overnight stakes victory to his credit this year, his connections believe there is still time to make a run at the title.\r\n&ldquo;It&rsquo;s obviously a very wide-open division right now, if somebody could take charge of it and finish strongly, they could make a strong case,&rdquo; trainer Todd Pletcher said Sunday. &ldquo;I&rsquo;ve always felt that Uncle Mo was the best horse of his generation, now we just got to come back and see if that&rsquo;s true or not.&rdquo;\r\nAnimal Kingdom, winner of the Kentucky Derby and a game second in the Preakness, would be considered a tepid division leader at the moment. But he will miss the remainder of the year with a slab fracture that might have occurred when he stumbled after being squeezed a few strides into the start of the Belmont Stakes.\r\nRuler On Ice, who won the Belmont, had not won a stakes race before then. Ruler On Ice is at Monmouth Park along with stablemate Pants On Fire, who has won the Louisiana Derby and Pegasus Stakes. The Haskell is a likely spot for one or both horses. On Monday, Kelly Breen, who trains both horses for owners George and Lori Hall, said no decision had been made yet on where those two would run.\r\n&ldquo;We&rsquo;re trying to figure out what&rsquo;s best for each individual horse, whether it&rsquo;s best to go to [the Haskell] with two or separate them,&rdquo; Breen said. &ldquo;The Travers is going to be a gigantic race for us, for Shackleford.&rdquo;\r\nBreen said that Ruler On Ice and Pants On Fire galloped together Sunday at Monmouth in a two-minute clip, or accelerated gallop. Both are scheduled to work at Monmouth this weekend.\r\nThe Haskell field also is likely to include Dominus, winner of the Grade 2 Dwyer at Belmont on July 2, according to co-owner George Bolton, and Rattlesnake Bridge, who won last Saturday&rsquo;s Long Branch Stakes at Monmouth. Dominus worked four furlongs in 51.02 seconds Monday at Saratoga. Astrology, a stablemate of Dominus and the third-place finisher in the Preakness, is likely headed to the Jim Dandy, according to Bolton. On Monday, Astrology worked five furlongs in 1:03.67 at Saratoga.\r\nOther horses expected for the Jim Dandy include Alternation, winner of the Peter Pan; Brilliant Speed, winner of the Blue Grass who was third in the Belmont; and Stay Thirsty, the Gotham winner who was second in the Belmont.\r\nOn Monday, Brilliant Speed returned to the work tab for the first time since the Belmont, working an easy half-mile in 51.59 seconds. Trainer Tom Albertrani said he would likely work Brilliant Speed three more times before the Jim Dandy. Stay Thirsty worked five furlongs on Sunday in 1:00.66, his third work since the Belmont.\r\nTo Honor and Serve, who like Brilliant Speed is owned by Live Oak Plantation, worked five furlongs in 1:00.68 on Sunday, his third breeze since returning from a strained suspensory ligament of his left foreleg that forced him off the Triple Crown trail. Trainer Bill Mott said To Honor and Serve, a multiple graded stakes winner at 2, is likely to be shortened up in distance at least for his first race back, which could mean the Amsterdam on Aug. 1 and or the King&rsquo;s Bishop, both at Saratoga.\r\nMucho Macho Man, who finished third in the Kentucky Derby, sixth in the Preakness, and seventh in the Belmont, has not started galloping yet, according to trainer Kathy Ritvo. She said that Mucho Macho Man would be vanned from Belmont to Saratoga this week and begin more serious training, though when and where he would return has not yet been determined.