[3] He also spent early years in Bryn Mawr, Pennsylvania, a Philadelphia suburb before relocating to Scottsdale, Arizona and attending Desert Mountain High School.

[4] The Baltimore Orioles selected Kelly in the 37th round of the 2007 Major League Baseball (MLB) draft, but he did not sign a contract.

After playing college baseball at Yavapai for two years, the Cleveland Indians took him in the 22nd round of the 2009 MLB draft, but again, he did not sign.

[2] Kelly advanced about one minor league level each season, beginning his career at Low-A in 2010 and reaching Triple-A for the first time in 2013.

Kelly signed with the SK Wyverns of the Korea Baseball Organization (KBO) ahead of the 2015 season.

In four seasons with SK Wyverns, Kelly pitched to a 48–32 record and a 3.86 ERA[2] while winning the 2018 Korean Series.

[8] On April 1, 2019, Kelly made his major league debut in a start versus the San Diego Padres.

He earned a win and recorded a quality start by totaling six innings, while allowing three runs and striking out three.

[9] After struggling for much of the season, Diamondbacks' manager Torey Lovullo called Kelly into his office and issued a warning that he was considering sending him down.

[12] Kelly won the National League Pitcher of the Month Award for July 2022 after pitching to a 1.31 ERA in six starts.