Oviedo arrived at Spring Training late, due to visa issues in his native Dominican Republic. He began the season on the disabled list, rehabbing at Durham.
Oviedo signed with the Rays prior to the 2013 season while recovering from Tommy John surgery to his right elbow, but he did not pitch for the Rays. The team re-signed Oviedo on Jan. 24 to a $1.5 million deal that can escalate to $2.9 million with incentives.
Riefenhauser made his Major League debut on Saturday night, retiring the four batters he faced. He retired the first two men he faced on Sunday, before running into trouble and eventually walking in the winning run.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.