The significant changes Efe Ajagba has made to his promising career are official.

Bob Arum’s Top Rank Inc. announced Wednesday that it has signed Ajagba to a promotional deal. Ajagba also confirmed in the announcement that he has changed trainers, from Ronnie Shields to Kay Koroma, and has hired prominent manager James Prince to represent him.

The Nigerian heavyweight prospect previously was promoted by Richard Schaefer’s Ringstar Sports and fought on Al Haymon’s Premier Boxing Champions cards.

“I made this decision to become a better boxer and to advance my career,” Ajagba said. “That’s why I signed with James Prince and Top Rank. When I return to the ring soon, you will see a new Efe Ajagba. Kay Koroma and I are working on my head movement and defense, as I seek to become a more well-rounded fighter.”

Prince and Ajagba announced on Instagram last month that they have teamed up. Ajagba didn’t mention then, though, that he would sign with Top Rank and change trainers.

The up-and-coming Koroma trains former IBF/IBO/WBA 154-pound champion Jarrett Hurd and is an assistant trainer for former WBO featherweight champion Shakur Stevenson. Shields is a respected veteran trainer who works with WBC middleweight champion Jermall Charlo and WBA super bantamweight champ Guillermo Rigondeaux.

The 6-feet-6, 240-pound Ajagba (13-0, 11 KOs), a 2016 Olympian for his native Nigeria, will make his Top Rank debut on an upcoming card to be determined either on ESPN or ESPN+, the network’s streaming service. Many of Ajagba’s bouts have been broadcast by FOX, FS1 and Showtime since he turned pro in July 2017.

“Efe Ajagba is one of the most gifted young heavyweights I’ve seen in quite some time,” Arum said. “He has immense physical tools and a great work ethic. I have the utmost confidence that we’re looking at a future heavyweight champion.”

The 26-year-old Ajagba’s power has made him a fan-friendly fighter over the past three years, but his defensive deficiencies have made him vulnerable at times.

Iago Kiladze dropped Ajagba in the third round of a fight FOX aired December 21 from Toyota Arena in Ontario, California. Ajagba, who had floored Kiladze during the second round, got up, regained control of their fight and knocked Kiladze to the canvas again in the fifth round.

Kiladze’s trainer threw in the towel late in the fifth round because the courageous Georgia native was taking a beating from the hard-hitting Ajagba. Referee Thomas Taylor stopped their bout at 2:09 of the fifth round.

The most noteworthy moment of Ajagba’s career came in August 2018, when Curtis Harper walked out of the ring just after the bell sounded to start their scheduled six-rounder at The Armory in Minneapolis. Harper, a huge underdog who reportedly was unhappy with his purse, was disqualified.

Ajagba stopped Romania’s Razvan Cojanu in the ninth round of his last fight, March 7 at Barclays Center in Brooklyn. Cojanu was knocked down during the eighth and ninth rounds before referee Ron Lipton ended their scheduled 10-rounder.

FOX televised Ajagba’s victories over Kiladze and Cojanu. 

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.