The Texas Rangers selected Erlin in the third round of the 2009 MLB draft. Erlin signed, bypassing the scholarship with Cal Poly. Erlin spent 2010 in Class-A ball and split 2011 between High-A and Double-A.
San Diego Padres
Texas traded Erlin along with fellow Double-A pitcher Joe Wieland to the Padres for reliever Mike Adams at the non-waiver trade deadline on July 31, 2011. Erlin was placed with the Double-A San Antonio Missions to finish the 2011 season, where he had a 1.38 ERA in six starts. He opened the 2012 season with San Antonio, but strained his elbow and developed tendinitis, making his last start for the team on May 12. He rehabbed the elbow late in the season with the Arizona Rookie League, and then pitched in the Arizona Fall League. Erlin joined the Tucson Padres of the Class AAAPacific Coast League for the 2013 season. He shuttled back and forth between Tucson and the Major League team, posting an 8-3 record and 5.07 ERA in 20 games with Tucson in 2013. In 2014 with three Padres minor league teams, he was 0-1 with a 5.87 ERA. In 2015 with El Paso, where he spent most of the season, he was 7-6 with a 5.60 ERA. Erlin was promoted to the Major Leagues on April 24, 2013, and made two appearances in relief before he was optioned back to Tucson on May 2. Erlin was recalled on June 1 for his first Major League start against the Toronto Blue Jays. Erlin won the first decision of his career in that start as the Padres defeated the Blue Jays, 4–3. He was optioned back to Tucson on June 2. Erlin was promoted for a third stint on June 26 to take the rotation spot of Clayton Richard, who went to the disabled list. Erlin was roughed up in successive starts in Boston and Washington in July, unable to get through the fifth inning in either start, and was optioned back to Tucson on July 8. Erlin was recalled late in the season to take the rotation spot of Edinson Vólquez. He fared better in his final stint of 2013, not allowing more than two runs in any of his five starts to finish the season. For the year, he went 3–3 with a 4.12 ERA with the Major League club. In 2014 with the Padres, he was 4-5 with a 4.99 ERA. He missed most of the season with left elbow soreness. In 2015 with San Diego, he was 1-2 with a 4.76 ERA. On May 3, 2016, Erlin was diagnosed with a partially torn UCL. He underwent Tommy John surgery on his left elbow that month and missed the remainder of the 2016 season. For the season, in 15.2 innings he was 1-2 with a 4.02 ERA. Following the non-tenders of Alexi Amarista and Tyson Ross after the 2016 MLB season, Erlin became the longest tenured Padre. Erlin returned to the Padres in 2018, making the Opening Day roster as a long reliever out of the bullpen. He moved to the starting rotation full-time after Tyson Ross and Jordan Lyles were waived. In 39 appearances, he finished 4-7 with an ERA of 4.21 in 109 innings. In 2019, Erlin recorded an ERA of 5.37 in innings. He became a free agent following the 2019 season.
Pittsburgh Pirates
On January 29, 2020, Erlin signed a minor league deal with the Pittsburgh Pirates. On July 20, 2020, Erlin had his contract selected to the 40-man roster.
Pitching style
Erlin has an average fastball in the range, but he is able to contrast it with an outstanding curveball and above-average changeup. He will also mix in cutters and sliders to give hitters a different look.
Personal life
Erlin's father, Rick, is the baseball coach at Scotts Valley.
