HALLANDALE BEACH, Fla. − A race that wasn’t even on the schedule when the meeting opened will have the eyes of the racing world riveted on Gulfstream Park shortly before 4:30 p.m. Saturday, when reigning juvenile champion and Kentucky Derby favorite Uncle Mo makes his 3-year-old debut in the $100,000 Timely Writer. The road to bringing such a stellar attraction as Uncle Mo to Gulfstream for the Timely Writer was a rocky one. The race was originally carded for Friday, March 11, at 1 1/8 miles. After some revisions, the Timely Writer was pushed back one day and shortened to a mile. Finding enough horses willing to take on Uncle Mo to fill the race was the next obstacle, but after a little prodding and tweaking, the Timely Writer finally came together with a field of six 3-year-olds, including four supplementary nominees at a cost of $600 apiece. The Timely Writer proved to be an attractive alternative to trainer Todd Pletcher and owner Mike Repole’s original choice for Uncle Mo’s 3-year-old debut, Saturday’s Grade 2 Tampa Bay Derby at 1 1/16 miles. Pletcher said he preferred the shorter distance and proximity to his winter headquarters at Palm Meadows. He also wanted to avoid a potential conflict with stablemate Brethren, who figures to amply fill the void left by Uncle Mo in Tampa. Uncle Mo has not started since clinching the 2-year-old championship with a 4 1/4-length victory over Boys At Tosconova in the Breeders’ Cup Juvenile on Nov. 6. The victory capped a perfect campaign that included a similarly one-sided triumph in the Grade 1 Champagne. Pletcher has mapped out a schedule for Uncle Mo that calls for two prep races before the Kentucky Derby; the second prep is the Grade 1 Wood on April 9. Uncle Mo has had six works in preparation for his return, several in company with recent Gotham winner Stay Thirsty, culminating with an easy half-mile in 48.87 seconds Sunday morning at Palm Meadows. “Everything has gone according to plan,” Pletcher said. “He’s worked every day he’s been scheduled to work, and Stay Thirsty’s performance last weekend has given us added confidence that he’s done enough since they were pretty much on the same schedule with Uncle Mo able to get in one additional work prior to his first start. He’s really been full of himself in the morning, and I’m very excited to get him going again and his season started.” Uncle Mo is also cross-entered in the Tampa Bay Derby, but he is expected to run at Gulfstream. It is unclear how many of the five 3-year-olds entered in the Timely Writer will actually be in the gate at post time. Madman Diaries is almost certain to give Uncle Mo a pretty good target to chase if he starts, having been on or near the lead in all seven previous outings. In the Breeders’ Cup Juvenile Turf, he led to midstretch before fading to fourth behind Pluck and Soldat. He also led at every call en route to his half-length decision in the six-furlong Sapling. “It looks like we’re the only speed in the field, but I’m not so sure I want to waste a race with my horse against the champ,” said Wesley Ward, who trains and is part owner of Madman Diaries. “I have other options I’m considering for him, so there is a good chance I still might not run him in this spot.” Rattlesnake Bridge finished full of run to win his only start, a six-furlong maiden-special-weight dash, despite racing greenly here Feb. 12. “We entered in an allowance race and it didn’t fill,” trainer Kiaran McLaughlin said, explaining why he plans to run Rattlesnake Bridge in a race he laughingly called the “Uncle Mo Handicap.” “We felt like we need to run to see where we stand, and it’s good timing moving forward from his maiden win,” McLaughlin said. “We didn’t want to hook up with Mo, obviously; none of us wanted to, but we needed to run, and a mile suits us well.” Rocking Out was an impressive debut winner in his lone start at 2, but disappointed when finishing third as the even-money favorite after setting a contested pace stretching to a mile for the first time Feb. 13.