In 2006, Luis Ayala blew out his elbow while pitching for Mexico in the World Baseball Classic. He had thrown 161.1 relief innings the previous two seasons and was leaned on heavily by the Mexican team. He hasn't been the same since.
The last two seasons, no pure reliever in baseball has thrown more innings than the 177 Saul Rivera has pitched. We just learned today that he'll be throwing for the Puerto Rican team in the WBC.
Other Nationals participating are Daniel Cabrera, Shairon Martis, Roger Bernadina, Pete Orr, Jose Castillo, and Jorge (not to be confused with alleged dirty bomber Jose) Padilla. But the one who really makes me nervous is Rivera. People tend to take RPs for granted, but Saul has been a rock for us. If he breaks down, a weak bullpen will become a disaster waiting to happen.