(REUTERS) – The Kentucky Derby is the first step toward Triple Crown glory and this year’s ‘Run for the Roses’ is more wide open than it has been in years after race favourite Omaha Beach was scratched due to injury.The betting line for today’s race went through a big shake-up after Omaha Beach, who was installed as the early 4-1 favourite, was pulled from the event on Wednesday after developing a non-life-threatening breathing problem.The absence of Omaha Beach opens the door for Hall of Fame trainer Bob Baffert, who is seeking to tie all-time trainer record for Kentucky Derby wins with six and now has the top three favourites in Game Winner, Roadster and Improbable. The top choice, at 9-2, is Game Winner, followed by Roadster and Improbable, who were both given 5-1 odds.But Baffert, who trained both American Pharoah and Justify to their Triple Crown wins in 2015 and 2018, respectively, is not getting ahead of himself going into the 1-1/2 mile race at Churchill Downs. “There are a lot of good horses in here,” said Baffert. “Unless we see something different on Derby Day, this is a nice evenly matched group of horses. I don’t see someone really popping off the screen.” Hall of Fame jockey Mike Smith, who rode Justify to a Triple Crown and was supposed to be aboard Omaha Beach today, was named yesterday as a late replacement for Corey Lanerie aboard 30-1 longshot Cutting Humor.Another horse to watch will be Maximum Security (10-1) as the Jason Servis-trained bay colt enters the Kentucky undefeated in his four starts. The Kentucky Derby field was reduced to 19 horses yesterday when longshot Haikal was scratched with an abscess on left hoof. As a result, the rail will remain empty as War of Will, who had drawn the No.1 post, will now break from the second gate.There is rain in the forecast today and while it may stop by the time the horses set off at 18:46hrs ET (2246 GMT) it is most certain they will contest the race on a wet track. Wet conditions will prove beneficial to some horses, perhaps none more so than War of Will (20-1), who last November raced on a muddy track at Churchill Downs in his first start on dirt and breezed to a five-length victory.But the Mark Casse-trained colt may need all the help he can get after an unfavourable draw has the son of hot Sire War Front starting from a post that has not produced a winner since 1978.