"I respectfully declined," Nathan said via text Wednesday. "It was a huge honor to be asked and I feel good, but I want to do right by the Rangers."
Texas signed Nathan prior to the 2012 season after he pitched the final few months of 2011 returning from Tommy John surgery (he missed all of 2010). Nathan, 38, had 37 saves and a 2.80 ERA and was named to the AL All-Star team last year.
Nathan pitched for the U.S. in 2006, the WBC's inaugural year.