Tolleson actually sustained the injury in January, and believes it flared up between an April 11 save for Albuquerque and his April 12 appearance for the Dodgers. In between, the Isotopes flew to Omaha and took a bus to Iowa, then he flew to Dallas en route to Phoenix.
"From all of that, it got tight," Tolleson said. "After I pitched Friday night, it got really bad."
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.