A few notes from around the boxing world:

• Although a formal announcement is due this week, Top Rank promoter Bob Arum told ESPN.com that newly-crowned junior lightweight world titleholder Vasyl Lomachenko will remain at 130 pounds rather than return to the 126-pound division to defend his featherweight world title. “He’s going to stay at 130,” Arum said. “We’re preparing for Oscar Valdez to fight for the vacant title on our July 23 card.”

  Lomachenko (6-1, 4 KOs), the two-time Olympic gold medalist from Ukraine, moved up in weight and spectacularly knocked out Rocky Martinez in the fifth round on June 11 at the Theater at Madison Square Garden in New York to win the junior lightweight belt. Mexico’s Valdez (19-0, 17 KOs) squares off with Matias Adrian Rueda (26-0, 23 KOs), of Argentina, for what will now be the vacant featherweight belt on the Terence Crawford-Viktor Postol HBO PPV undercard at the MGM Grand in Las Vegas.

• While serving as an analyst on Saturday night’s Premier Boxing Champions card on NBC, rising welterweight star Errol Spence Jr. (20-0, 17KOs), the 2015 ESPN.com prospect of the year, announced that he will headline a special PBC on NBC card on Aug. 21, a Sunday night, following Olympic coverage on the network. “I’m back on Aug. 21,” Spence said. “The world title chase continues.”

  The site and opponent have not been announced but it is likely that Spence, 26, of Desoto, Texas, will take on Italy’s Leonard Bundu (33-1-2, 12 KOs) in a world title elimination bout for the right to become the mandatory challenger for the belt held by England’s Kell Brook (36-0, 25 KOs), who is first due to face Jessie Vargas in a title unification bout in September. The 41-year-old Bundu has won two fights in a row since his only defeat, a shutout decision to Keith Thurman in an interim title bout in Las Vegas in December 2014.

• British lightweight Luke Campbell (13-1, 11 KOs), a 2012 Olympic gold medalist, will next face former junior lightweight world titleholder Argenis Mendez on July 3 at First Direct Arena in Leeds, England, promoter Eddie Hearn of Matchroom Boxing announced. The fight will take place on the undercard of Leeds featherweight Josh Warrington (23-0, 4 KOs) taking on Ireland’s Patrick Hyland (31-2, 15 KOs), who got stopped in the second round by world titleholder Gary Russell Jr. on April 16. Campbell will be seeking his second win in a row since an upset decision loss to Yvan Mendy in December. The Dominican Republic’s Mendez (23-4-1, 12 KOs), who is based in Brooklyn, New York, will be Campbell’s most notable opponent yet, although he is coming off a blistering fifth-round knockout loss to up-and-comer Robert Easter on April 1.