On Wednesday, Jim Chairusmi of the Wall Street Journal reported the deal with Phoenix Thoroughbreds will become official Thursday, and the NFL star plans to meet his namesake colt in the days leading up to the May 5 race at Churchill Downs in Louisville, Kentucky.
"It will be a new experience. Hopefully it will be something I like. I like new hobbies," Gronkowski said.
Gronkowski, who was bred in Kentucky before getting moved overseas, qualified for the first race of the Triple Crown as the top finisher in the European Road to the Kentucky Derby.
The Jeremy Noseda trainee has won each of his past four starts, highlighted by his triumph in last month's Burradon Stakes at Newcastle Racecourse in England.
Gronkowski is listed as an early 30-1 long shot in the Run for the Roses by Derek Simon of US Racing. Official odds won't be available until after the post-position draw the week of the race.
Meanwhile, the Patriots tight end skipped the start of the team's offseason workouts Monday and hasn't decided whether he's going to play in 2018, per ESPN's Adam Schefter.
Gronk told Chairusmi his stake in the Derby horse is an "investment" as well as an opportunity to have some fun.