Rodriguez has pitched in each of the past 10 seasons and has a career record of 91-94 and a 4.06 ERA. He pitched in just six games for the Pirates last season and went 0-2 with a 6.75 ERA.
"Wandy gives us an experienced starting option at Round Rock if we have an early need," general manager Jon Daniels said. "He threw well in winter ball and again this spring."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.