Your browser does not support iframes\r\nLOUISVILLE, Ky. &ndash; As soon as Uncle Mo crossed the wire more than four lengths in front of the field in the Breeders&rsquo; Cup Juvenile here at Churchill Downs last fall, he was universally held as the strong favorite for the Kentucky Derby. It was a position he maintained for five months. But the entire perception of this Saturday&rsquo;s 137th Derby changed on April 9, when Uncle Mo suffered the first loss of his career, in the Wood Memorial.\r\nIn the immediate aftermath of that race, trainer Todd Pletcher and owner Mike Repole put out a press release that said Uncle Mo was suffering from a gastrointestinal infection. As a result, Uncle Mo underwent treatment, overseen by Kentucky-based veterinarian Dr. Doug Byars. Uncle Mo&rsquo;s training schedule had to be adjusted. He has had just two works since the Wood, the first of which was delayed until April 26. Following his final breeze on Sunday morning here, he had an easy jog on Monday, merely walked the shed row at his barn on Tuesday during a driving rainstorm, and just jogged one mile, accompanied by a stable pony, on Wednesday.\r\nKENTUCKY DERBY FIELD: Post positions and Watchmaker's odds\r\nThe Wood loss, subsequent training schedule, and concerns over Uncle Mo&rsquo;s ability to handle the Derby&rsquo;s 1 1/4 miles have made the onetime heavy favorite one of the biggest question marks in this Derby. Another hurdle was added early Wednesday evening, when Uncle Mo drew post 18 in a field of 20 when post positions were drawn for Saturday&rsquo;s race.\r\nTrainer Todd Pletcher later said he was satisfied with the draw, but his body language told otherwise when the number 18 was called out. He slowly shook his head with a resigned look while sitting alongside Repole.\r\nAll this has made the perception of this Derby as being wide-open, not one-sided. Uncle Mo, in fact, is only the second choice on the morning lines of Mike Battaglia of Churchill Downs and Mike Watchmaker, Daily Racing Form&rsquo;s national handicapper, both of whom made Florida Derby winner Dialed In, who drew post 8, the 4-1 favorite. Battaglia has Uncle Mo at 9-2, while Watchmaker has him at 5-1.\r\nIn addition to Uncle Mo, there were several significant developments at the draw, most notably Archarcharch getting the rail, a post that hindered favored Lookin At Lucky in last year&rsquo;s race. But Archarcharch is best when he drops back and makes one run, so the post might not be as bad as it first looks.\r\nArcharcharch and Comma to the Top were the final two horses to have their posts drawn. Posts 1 and 6 remained. When 6 was called for Comma to the Top, trainer Peter Miller had a beaming smile, relieved his speed horse did not end up on the inside.\r\nBy contrast, Nehro, second to Archarcharch in the Arkansas Derby, landed post 19, and Watch Me Go drew the far outside post.\r\nA maximum of 20 horses can run in the Derby, but there were 22 entry slips turned in Wednesday morning. In situations like that, earnings in graded stakes are used to determine the starting field. Sway Away and Ruler On Ice, in that order, had the least in their piggy banks, so they were excluded. There is no also-eligible list for the Derby.\r\nThis is the eighth straight year that at least 20 horses were entered in the Derby. If all 20 run, the purse will be $2,196,800, with $1,436,800 to the winner.\r\nWith 20 horses entered, two starting gates will be used. Fourteen horses can fit in the main starting gate, and there will be six in an adjacent auxiliary gate.\r\nPletcher, who won the Derby for the first time in his career last year with Super Saver, also entered Stay Thirsty, who drew post 4. Stay Thirsty is also owned by Repole. Pletcher is one of two trainers who entered two horses in the Derby. The other is Mike Maker, who has Derby Kitten and Twinspired.\r\n&ldquo;Last year, I rooted for Todd Pletcher, and didn&rsquo;t care which horse of his won,&rdquo; Repole said. &ldquo;This year, I&rsquo;m rooting for Todd Pletcher, and I don&rsquo;t care which one wins.&rdquo;\r\nStay Thirsty finished seventh in the Florida Derby in his last start. He wore blinkers for the first time that day, but Pletcher said they will be removed for the Derby.\r\nStay Thirsty might be flying under the radar. He has looked well all week, and had a sharp final work, in company with Uncle Mo, on an off track on Sunday.\r\n&ldquo;To me, [that was] the best work Stay Thirsty has had,&rdquo; Pletcher said. &ldquo;Not just the way he worked, but the gallop-out. Obviously an off track would favor him if it rained Saturday. He&rsquo;s improving. He&rsquo;s had a good three weeks. He&rsquo;s filled out.&rdquo;\r\nBut it is Uncle Mo who has carried the hopes of the barn for months, and who has been the center of attention all week. His light training schedule has made him the talk of the track.\r\nPletcher said he suspected something was wrong with Uncle Mo following the Wood because &ldquo;what we saw was a performance that was not up to his standards.&rdquo;\r\n&ldquo;So, we started looking,&rdquo; he said.\r\n&ldquo;The timing was critical,&rdquo; Pletcher said. &ldquo;Hopefully we can get it all sorted out. He&rsquo;s made good strides. We&rsquo;re constantly evaluating his treatment. We&rsquo;ve scaled back some already.&rdquo;\r\nPletcher said the distance of the Wood, which marked the first time Uncle Mo raced as far as 1 1/8 miles, was not the reason for his loss.\r\n&ldquo;It wasn&rsquo;t about the mile and an eighth,&rdquo; he said.\r\nPletcher said the loss was frustrating.\r\n&ldquo;On a scale of 1 to 100, it was 200,&rdquo; Pletcher said. &ldquo;To lose with the best horse is always frustrating.&rdquo;\r\nPletcher said he still believes that the Uncle Mo who ran in last year&rsquo;s Breeders&rsquo; Cup Juvenile is the best horse of this crop. The question that lingers, though, is whether the Uncle Mo of Nov. 6 is the same Uncle Mo today.\r\n&ldquo;I haven&rsquo;t seen anyone in this group turn in as devastating a performance as he has,&rdquo; Pletcher said. &ldquo;But that doesn&rsquo;t mean someone else won&rsquo;t.&rdquo;\r\nThe Derby is the 11th race on a 13-race card scheduled to begin at 10:30 a.m. Eastern time Saturday. Post time for the Derby is listed as 6:24 p.m., though is likely to go off a few minutes later.\r\nThe Derby will be televised live by NBC Sports in a three-hour telecast beginning at 4 p.m. The cable station Versus will televise the Derby undercard, beginning at 11 a.m., then return at 7 p.m. for a half-hour recap show.\r\nAccording to the National Weather Service, the forecast for Saturday is for a 50-percent chance of rain, with scattered thunderstorms, and a high of 73 degrees. The forecast was for dry weather Wednesday and Thursday, but there is a 40-percent of chance of showers for Friday.