Kubrat Pulev has been impressed by what he has seen while studying Rydell Booker.

Though 38, Pulev views the Detroit-based Booker as a capable boxer who could ruin his journey toward another heavyweight title shot if Pulev isn’t at his best Saturday night. Pulev could’ve waited to battle the winner of the Andy Ruiz Jr.-Anthony Joshua rematch, but he opted to stay busy by battling Booker in a 10-round fight ESPN+ will stream from Fresno, California.

“He’s a good boxer, with a lot of experience and speed,” Pulev told BoxingScene.com. “He’s quick and slick, and he’s technically very good. But I think I’m at a different level and I must beat him.”

If Pulev beats Booker, the 38-year-old Bulgarian contender will remain the IBF’s mandatory challenger for whomever wins the immediate rematch between Ruiz (33-1, 22 KOs), the IBF/IBO/WBA/WBO champion, and Joshua (22-1, 21 KOs) on December 7 in Diriyah, Saudi Arabia. If Pulev (27-1, 14 KOs) doesn’t get his shot at the winner before May 31, the winner would be stripped and Pulev would face the next ranked, available contender for the IBF belt.

“I’m ready for the next fight,” Pulev said. “But I’m concentrating on this fight because this fight is not easy. This fight is very, very important for me. I’m prepared for this fight. I’ve trained hard for this fight. And this is most important for me.”

Detroit’s Booker (26-2, 13 KOs) tested undefeated prospect Jermaine Franklin on April 13 in Atlantic City, New Jersey. Franklin (20-0, 13 KOs), of Sagniaw, Michigan, won that 10-round bout by unanimous decision, but Pulev thought it was more competitive than the scorecards indicated (99-91, 98-92, 98-92).

“I watched this fight,” Pulev said. “He lost, but it was a close fight. But I’m a better boxer, and that’s it.”

The Pulev-Booker bout will be streamed by ESPN+ just before its main event from Chukchansi Park, the home stadium of the Fresno Grizzlies, the World Series champion Washington Nationals’ Triple-A affiliate. In that 12-round bout, Jamel Herring (20-2, 10 KOs), a former Marine from Coram, New York, will make his first defense of the WBO junior lightweight title against mandatory challenger Lamont Roach (19-0-1, 7 KOs), of Upper Marlboro, Maryland.

ESPN+ will start streaming the Herring-Roach undercard at 6:30 p.m. EST/3:30 p.m. PST.

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