Nelson began 2014 back at Triple-A Nashville, and dominated the Pacific Coast League to the tune of a 10–2 record, 1.46 ERA, and 114 strikeouts.

[5] He made one spot start for Milwaukee against the Miami Marlins due to a minor injury suffered by Yovani Gallardo on May 25, and recorded his first major league win, pitching 5+2⁄3 scoreless innings with 3 walks and 6 strikeouts.

On July 10, Nelson was recalled again to join the starting rotation in place of the home run-prone Marco Estrada.

[6] Nelson sustained an injury on September 17 against the St. Louis Cardinals when Tommy Pham hit a line drive that ricocheted off his head.

The next day, on September 9, it was revealed that he was diagnosed with a right rotator cuff strain and a partial anterior labrum tear, meaning that he would take no further part in any action for the remainder of the 2017 season.

[10] On January 7, 2020, Nelson signed a one-year, $1.25 million, contract with the Los Angeles Dodgers that also included an option for 2021.

[12] On October 30, 2020, the Dodgers declined their team option on Nelson's contract for the 2021 season, making him a free agent without having thrown a pitch for the organization.

He missed 18 games with forearm inflammation and another 14 with a left lumbar strain before he was shut down in early August when it was determined that he would need both Tommy John surgery and a flexor tendon repair in his right arm.