On May 14, 2010, Wagner was traded to the Oakland Athletics in exchange for cash considerations.[2] He spent the remainder of the year with the Double-A Midland RockHounds, posting a 6-2 record and 3.70 ERA with 45 strikeouts across 33 relief appearances.
Wagner began the 2011 season with Midland, and later received a promotion to the Triple-A Sacramento River Cats. On August 30, 2011, Wagner was selected to the 40-man roster and promoted to the major leagues for the first time.[citation needed]
San Diego Padres
On May 28, 2012, Wagner was waived by the Athletics and claimed by the San Diego Padres.[3][4] He spent the remainder of the year with the Triple-A Tucson Padres, posting a 3-1 record and 5.44 ERA with 32 strikeouts over 43 innings of work. Wagner was designated for assignment following the acquisition of Thad Weber on August 23.[5] He became a free agent on November 3.
Toronto Blue Jays
On November 15, 2012, the Toronto Blue Jays signed Wagner to a minor league contract with that included an invitation to spring training.[6] The deal was announced by the Jays on November 21.[7]
Wagner began the 2013 season with the Triple-A Buffalo Bisons. He was called up by the Toronto Blue Jays on May 29.[8] Wagner recorded his first career win in a game on June 7 against the Texas Rangers, pitching 11⁄3 innings in relief. After posting a 2–3 record with a 3.26 ERA and 16 strikeouts in 20 appearances, Wagner was optioned to Triple-A Buffalo on July 21 to make room on the 25-man roster for Melky Cabrera's return from the disabled list.[9] Wagner was recalled when Cabrera went on the disabled list on August 2, 2013.[10]
The Blue Jays optioned Wagner to Buffalo on March 14, 2014. He was recalled by the Blue Jays on April 9,[11] and sent back to Buffalo on April 26. After a consultation with Dr. James Andrews on August 12, it was determined that Wagner would require Tommy John surgery and was expected to miss the rest of the 2014 season as well as the entire 2015 season.[12] In 10 appearances prior to the injury, he had recorded an 8.10 ERA with six strikeouts over 10 innings of work. Wagner was designated for assignment by the Blue Jays on September 1.[13] The following day, Wagner was released.[14]
Tampa Bay Rays
On September 12, 2014, Wagner signed a two-year minor league contract with the Tampa Bay Rays, that included an invitation to 2016 spring training.[15] He returned to action in 2016, posting a 4.44 ERA with 48 strikeouts across 42 appearances split between the High-A Charlotte Stone Crabs and Triple-A Durham Bulls.
Wagner began the 2017 season with Triple-A Durham, posting an 0-1 record and 3.07 ERA with 41 strikeouts and three saves across 32 appearances (one start). He was released by the Rays organization on August 2, 2017.[16]
New York Mets
On August 15, 2017, Wagner signed a minor league contract with the New York Mets.[17] Wagner made 8 appearances for the Triple–A Las Vegas 51s, tallying 10+1⁄3 scoreless innings with 11 strikeouts. He elected free agency following the season on November 6.[18]
Saitama Seibu Lions
On December 13, 2017, Wagner signed with the Saitama Seibu Lions of Nippon Professional Baseball (NPB).[19] He made 36 appearances for Seibu during the 2018 season, logging a 2-1 record and 4.22 ERA with 24 strikeouts and one save over 32 innings of work. Wagner was placed on waivers on September 28, 2018.[20]
