According to Brown, the decision was based on how the Curlin colt has trained in recent days at Belmont Park, including a gallop Sunday.
"The horse trained great again this morning and has bounced out of the Derby really well," the trainer said of Good Magic, who is owned by e Five Racing Thoroughbreds and Stonestreet Stables. "(The decision) came down to our horse and how he was doing. It's a huge opportunity, and the way he came out of the race, he deserves another shot."
The margin between the two runners in the Derby was 2 ½ lengths, and Brown is hopeful his champion 2-year-old male of 2017 can cut into or eliminate that distance with a new set of circumstances in the Preakness.
"Both horses are going to do things they've never done before—run on two weeks' rest and run at Pimlico," the trainer said. "We're hopeful our horse responds to that well. If you're asking how we're going to close the gap of a couple lengths, that's it."
Brown won his first classic in last year's Preakness with Cloud Computing, but he faces a significantly different scenario this year for his return to Baltimore. In 2017, he ran Practical Joke (fifth) in the Derby, then brought a fresh contender in Cloud Computing to the Preakness and upset Derby winner Always Dreaming and champion Classic Empire .
"It's different because last year we came with a fresh horse," Brown said. "This time, I have a horse on two weeks' rest going against a really good horse (in Justify)."
Good Magic will ship from New York to Baltimore on Monday.
Another Derby runner, Lone Sailor, who finished eighth but encountered trouble, is also committed to run in the Preakness. Owner G M B Racing took to Twitter to make the announcement. Prior to the Derby the Majestic Warrior colt finished a neck second to Noble Indy in the Twinspires.com Louisiana Derby.
"Not looking to ruffle anybody's feathers, but the Derby time, particularly the last half-mile, was :53 and change," said Lone Sailor's trainer, Tom Amoss. "It's hard to feel off that race that the Preakness isn't a wide-open race.
"I'm not saying Lone Sailor is better than those horses, but he had a bad enough trip in the Derby that he deserves another shot."
The third Derby horse who was under consideration for the Preakness was Ruis Racing's Bolt d'Oro, who finished 12th in the run for the roses, but owner/trainer Mick Ruis said Sunday the Medaglia d'Oro colt will not run in Baltimore May 19.