NEW YORK — Kentucky Derby winner Animal Kingdom on Wednesday was made the 2-1 morning-line favorite to become the 12th horse to win both the Derby and the Belmont Stakes in Saturday’s 143rd renewal of the Triple Crown’s oldest and longest leg.

He will break from the No. 9 post, and his trainer, Graham Motion, expects jockey John Velazquez to keep Animal Kingdom much closer to the front of the pack in the mile-and-a-half race than he was in the Preakness Stakes.

In that race, Animal Kingdom dropped far back after not liking the dirt kicked in his face and therefore had to work harder in the stretch drive, ending with a half-length defeat to Shackleford.

“I think Johnny and Animal Kingdom were surprised how much dirt came back,” Motion said. “Both have learned since then, and he won’t be out of touch. I think he’s going to have to be close in a mile-and-a-half race.”

Shackleford (9-2) will start from the No. 12 post, the farthest outside, leaving his rider, Jesus Castanon, little choice but to gun his colt early to clear the field and establish position on the rail.

“It doesn’t really matter because he likes to run from the front anyway,” his trainer, Dale Romans, said of Shackleford, who led in the Derby before finishing fourth and then in the Preakness hit the homestretch in first place. “We’re comfortable setting the pace. He’s fast enough that he’ll be able to break and clear everyone anyway.”

The Belmont oddsmaker, Eric Donovan, apparently believes the public will be betting that a fresh horse is going to disrupt the rubber match between Animal Kingdom and Shackleford: Nehro is the morning-line’s second choice at 4-1.

Nehro, a son of Mineshaft, finished second in the Derby and then skipped the Preakness. He has only one victory in six starts, with runner-up finishes in the Louisiana and Arkansas derbys.

“We’ve got three seconds in the last three Derbys,” said Brad Weisbord, the racing manager for Nehro’s owner, Zayat Stables. “We hope to shed the bridesmaid’s tag and get the win. Nehro is very versatile, so he really can be anywhere.”

It will be just the 22nd time in Triple Crown history that the Derby and Preakness winners have squared off in the Belmont, and the first since Afleet Alex defeated Giacomo in 2005 to sweep the second and third legs of the Triple Crown.

Motion and Romans each captured Triple Crown races for the first time this year and have good-naturedly stoked a rivalry between the colts.