Trainer Dale Romans said his 3-year-old horse was ready for a rematch with Kentucky Derby champ Animal Kingdom following Shackleford's five-furlong work in 1 minute, 00.30 seconds at Belmont Park.
"I am excited he's doing so well and coming into the race the right way," Romans said. "I think he's going to be very competitive."
The New York Racing Authority said in a written statement the June 11 race will mark the 22nd time in the history of the Triple Crown that the winners of the Derby and Preakness have met in the Belmont, the last and longest race in the venerable series.
Shackleford edged Animal Kingdom in the stretch of the Preakness after placing fourth in the Derby.
Exercise rider Tammy Fox took Shackleford on the main track with times of 12.41 seconds for the first eight, 36.26 for three furlongs and 1:00.33 for five. He galloped out in 1:14.21.
"I thought he went around there really well and it looked like he did everything the way he was supposed to," said Romans, who said Saturday's run was a normal workout for Shackleford.