Wagner played college baseball at the University of Utah for the Utah Utes from 2010 to 2012 as a relief pitcher. As a sophomore in 2011, Wagner set the Utes single-season saves record with 12 and finished his career with a school record 17 saves.[1] Overall, he appeared in 57 games in his three seasons in Utah, going 6–10 with a 2.73 earned run average (ERA) and 90 strikeouts in 99 innings.
The Brewers promoted Wagner to make his major league debut on May 31.[7] After one start, they optioned him back to the Biloxi Shuckers of the Southern League.[8] Wagner made 3 starts for the Brewers in 2015, posting an 0–2 record, 7.24 ERA, and 5 strikeouts in 132⁄3 total innings.[9]
Wagner was claimed off waivers by the Texas Rangers on November 18, 2016.[11] Wagner finished his 2016 season with a 1.80 ERA.[12] On April 19, 2017, Wagner was outrighted off of the roster. He spent the 2017 season with the Round Rock Express.
In 2018, Wagner played in 25 games (including 18 starts) for the Double–A Frisco RoughRiders and Triple–A Round Rock, accumulating a 4.76 ERA with 59 strikeouts across 104 innings pitched. He elected free agency following the season on November 2, 2018.[13]