Joe Nathan of the Minnesota Twins and B.J. Ryan of the Toronto Blue Jays are skipping the World Baseball Classic, leaving the United States without a pair of first-rate relievers.

A three-time All-Star, Nathan bowed out Sunday after experiencing soreness in his pitching shoulder the previous five days.

"I think we backed off it early enough to where it won't be an issue," said Nathan, who aggravated the AC joint, which connects the collarbone and clavicle at the top of the shoulder.

Ryan, a two-time All-Star, decided to stay in spring training with Toronto and tune up for the regular season.

"This was an especially tough decision because of the honor of playing for my country, but I feel it is (in) the best interest of Team USA and the Toronto Blue Jays organization to not participate," the left-hander said in a statement released by USA Baseball early Monday. "I do not see it as being fair to my USA teammates, my Blue Jay teammates or myself to try to compete when my mechanics and delivery are not where they need to be in order to perform at the highest level."