RingTV.com has learned that Robert Guerrero has suffered a shoulder injury that will force the cancelation of his fight with Marcos Maidana, which was scheduled for Aug. 27.

The fighters were to vie for what the WBA calls its “regular” title on HBO in what would’ve been Guerrero’s first fight at 140 pounds.

Neither Golden Boy Promotions CEO Richard Schaefer nor Guerrero’s publicist could be reached for comment. An official from HBO said that he had no knowledge of the injury or the status of the Guerrero-Maidana fight.

The extent and severity of Guerrero’s injured shoulder is not known, but he was “on his way to get it medically checked,” according to a source.

The injury is the latest setback in what has been an inspirational but sometimes-difficult career for the 28-year-old Guerrero (29-1-1, 18 knockouts), who is coming off of a one-sided, unanimous decision victory over Australia’s hard-punching Michael Katsidis (28-4, 23 KOs) in April.

Guerrero chose in March of last year to pull out of a scheduled clash with Katsidis in order to be with wife Casey during her recovery from a bone marrow transplant. Guerrero’s often had to drive 50 or so miles back and forth from the hospital to their home in Gilroy, Calif., to care for their two young children, Robert Jr., 4, and, Savannah, 6.

Guerrero’s devotion to his wife and family were recognized when he received The Bill Crawford Award for Courage In The Face of Adversity from the Boxing Writers Association of America.

Assured that Casey’s cancer was in remission, Guerrero returned to the ring with an eighth-round knockout of Roberto David Arrieta in April of last year.

Guerrero was after his 14th consecutive victory against Maidana (30-2, 27 KOs). He last suffered defeat by a split-decision to Gamaliel Diaz in December 2005 but won their rematch with a sixth-round knockout in June 2006.

A two-time IBF featherweight and one-time IBF super featherweight beltholder, Guerrero’s comeback has included unanimous decisions over former four-time titleholder and Cuban Olympic gold medalist Joel Casamayor (38-5-1, 22 KOs) in July and a Vicente Escobedo (23-3, 14 KOs) in November.

Guerrero overcame a re-injured left hand to defeat Escobedo.

Lem Satterfield can be reached at [email protected]