By Dan Ambrose: Robert Guerrero (29-1-1, 18 KO’s) has reportedly injured his left shoulder during a sparring session on Wednesday night and the severity of the injury is going to keep him out of his August 27th fight against WBA light welterweight champion Marcos Maidana (30-2, 27 KO’s).

Guerrero and Maidana were supposed to be fighting at the HP Pavilion in San Jose, California. However, Guerrero’s left shoulder is going to keep him out of that fight. Currently, Guerrero is flying to San Jose to have a local doctor examine the shoulder. As for Maidana, there’s no word of when he’ll be fighting next. Obviously it won’t be in San Jose on the 27th, because that was Guerrero’s hometown and he’s not going to be fighting there without Guerrero.

One would hope that Guerrero’s injury isn’t severe and that the fight can take place perhaps in September or October.

This was going to be Guerrero’s big test to see if he could handle the power from one of the biggest punchers in the light welterweight division in Maidana. Guerrero was moving up to 140 from the lightweight division, which he only briefly fought in after moving up from super featherweight in 2010.

Guerrero’s promoters from Golden Boy Promotions are high on him, and see him as a potential champion at light welterweight and perhaps welterweight. Maidana could be the one to get in the way of Guerrero’s promoters dreams for him though if they can ever get Guererro in the ring in one piece. Guerrero is still a question mark, however, because he showed little power in his last fight at lightweight against Michael Katsidis. At light welterweight, Guerrero could be even weaker and just another slender-looking boxer without power.