LAS VEGAS (AP) _ Erik Morales will have a new opponent to replace Wayne McCullough when he defends his WBC super batamweight title May 8.

Promoter Bob Arum said McCullough injured his back in training and will be replaced by Juan Carlos Ramirez of Mexico.

Ramirez is 17-1 with seven knockouts.

Arum said Ramirez had been training for a May bout in Mexico when he got the call to replace McCullough, whose left lower back was injured when hit by a punch in training.