Santa Cruz, out of action for the last two weeks, may remain unavailable for the fixtures on March 28 in Montevideo and April 1 in Quito.

"I gave up training two weeks ago," he told the Puro Futbol radio show.

"I will not play this Saturday's match (against West Ham) either.

"It is a tendinitis I've been carrying for a long time and I already played some matches with pain."

Paraguay and Blackburn's medical staff are due to discuss how to manage the injury.

"Not training does not help my physically," Santa Cruz added.

"It is a very difficult situation. We'll have a talk with the medical staff tomorrow."

Paraguay head coach Gerardo Martino will announce his squad tomorrow for both matches.

His team lead the World Cup South American Qualifying Zone on 23 points.