LOUISVILLE, Ky. – Shackleford sharpened for his role as the likely favorite in the $1 million Haskell Invitational at Monmouth Park by breezing five furlongs over a fast track in a swift 58.60 seconds on a hot, humid Sunday morning at Churchill Downs. Shackleford, the 2011 Preakness winner, is scheduled to ship overnight Monday and arrive early Tuesday at Monmouth in Oceanport, N.J., where the annual meet highlight, the Grade 1 Haskell, will be run next Sunday, July 31. With Tammy Fox aboard, Shackleford worked right after the regularly scheduled harrow break and without company, going in splits of 12.60 seconds, 23.60, 35.40, and 46.60, with a six-furlong gallop-out time of 1:13.40. “He did it easy,” said Fox, life partner of the colt’s trainer, Dale Romans. “I didn’t move a muscle on him. It’s scary to think what he would’ve done with company. All I know is he’s ready to go.” The Shackleford work came hours before the Kelly Breen duo of Ruler On Ice and Pants On Fire were scheduled to work a half-mile together shortly after the fifth race (post time, 2:50 p.m. Eastern) on the Sunday card at Monmouth. Jose Valdivia Jr. will be back aboard Ruler On Ice, the 2011 Belmont Stakes winner, while Elvis Trujillo will be up on Pants On Fire. Other prospective starters for the 1 1/8-mile Haskell include Astrology, Coil, Concealed Identity, and JJ’s Lucky Train.   The speedy Shackleford will be turning back in distance in his first race since the Triple Crown series when he runs in the Haskell. “He’s shown he can go longer, but you’d have to think a mile and an eighth is right up his alley,” Romans said Sunday morning from Saratoga. “From everything Tammy said, we’re all set.”   Shackleford, owned by Mike Lauffer and Bill Cubbedge, now has three straight Sunday works at Churchill since getting a brief respite following the Belmont. The colt breezed a half-mile in 48.40 seconds on July 10 and five furlongs in a bullet 59.60 on July 17.   After working Shackleford, Fox also was aboard Sassy Image in a solo workout. The winner of three straight graded stakes and a leading candidate for top female sprinter, Sassy Image went a half-mile in 47.20. Her main goal this summer is the Grade 1 Ballerina on the Aug. 27 Travers undercard at Saratoga.