Ra’esse Aleem will fight on the Brandon Figueroa-Stephen Fulton undercard, but not against the opponent many boxing fans expected.

BoxingScene.com has learned that Aleem will defend a version of the WBA’s super bantamweight championship against Eduardo Baez on September 18. Showtime will televise the Aleem-Baez bout as the 12-round opener of a doubleheader from Park Theater at Park MGM in Las Vegas.

Numerous outlets reported that Aleem (18-0, 12 KOs) would face former IBF and WBA champ Daniel Roman (29-3-1, 10 KOs) in this “Showtime Championship Boxing” doubleheader, but that fight didn’t materialize. Showtime will televise only two boxing matches that night, rather than offering its customary three-bout broadcast, because the network will televise a mixed martial arts show, “Bellator MMA 266,” from SAP Center in San Jose, California, immediately following a boxing telecast scheduled to start at 9 p.m. EDT.

The 31-year-old Aleem, a Las Vegas resident raised in Muskegon, Michigan, won the WBA interim 122-pound championship by stopping Vic Pasillas (16-1, 9 KOs) in the 11th round of his last fight. Aleem dropped Pasillas four times during that scheduled 12-rounder January 23 at Mohegan Sun Arena in Uncasville, Connecticut.

The WBA might promote Aleem to the status of world champion because it stripped that title from Figueroa (22-0-1, 17 KOs). Figueroa still will defend his WBC super bantamweight title when he faces Philadelphia’s Fulton (19-0, 8 KOs), the WBO junior featherweight champ.

The Mexican-born Baez, 26, has won eight straight bouts, but he’ll take a step up in class against Aleem. In his most recent action, the 5-feet-9 Baez (19-1-2, 6 KOs), of Calexico, California, unanimously out-pointed Puerto Rico’s Abimael Ortiz (9-1-1, 5 KOs) in an eight-rounder NBC Sports Network aired as part of its “Ring City USA” series March 25 from San Juan.

Baez has lost only a six-round unanimous decision to fellow Mexican Mauricio Lara (22-2, 15 KOs). Mexico City’s Lara upset former IBF featherweight champ Josh Warrington (30-1, 7 KOs) by ninth-round technical knockout February 13 at Wembley Arena in London.

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