Rallis signed a developmental contract with WWE in early 2014 and began training at the WWE Performance Center. He made his professional wrestling debut on December 18 at a NXT live event in Tampa, Florida under the ring name Digg Rawlis. He made his televised debut on the May 27, 2015, episode of NXT, working as an enhancement talent alongside Elias Samson in a defeat to Blake and Murphy. Rawlis made further occasional televised appearances as an enhancement talent during 2015, losing to The Hype Bros and Samoa Joe. In August 2015 he adopted the new ring name Riddick Moss, a tribute to former NFL player Randy Moss. In October 2016, Moss began teaming with Tino Sabbatelli, with the two competing in the 2016 Dusty Rhodes Tag Team Classic where they were defeated in the first round by TM61 on the October 12 episode of NXT. Moss made a further appearance on the January 4, 2017, episode of NXT, again teaming with Sabbatelli in a defeat to The Revival. Moss and Sabbatelli made another appearance on the May 10 episode of NXT, losing to #DIY. The duo had their first televised victory on the October 25 episode of NXT, defeating the team of Oney Lorcan and Danny Burch. In early 2018, Moss and Sabbatelli entered the Dusty Rhodes Tag Team Classic losing to Sanity in the first round. On April 25 during a match with Heavy Machinery, Sabbatelli ditched Moss, thus ending the team. In May 2018, he tore his Achilles tendon and would require several months to recuperate. He would make his return from injury on a November 30, 2018 live event, losing to Matt Riddle after a surprise appearance. In March 2019, he started being managed by Robert Strauss at NXT live events. On the May 8, 2019 episode of NXT, Moss competed in his first televised match since his injury in a loss to Raul Mendoza.
Moss' contract was coming up this year, but it was reported he signed an extension. On the January 27, 2020 episode of Raw, Moss made his debut, accompanying Mojo Rawley to the ring for his WWE 24/7 Championship match against No Way Jose, where Moss was billed as Rawley's 'offensive lineman'. While Rawley won the initial match, he lost the championship to R-Truth moments later; however, Moss assisted Rawley in regaining the title just seconds later. On the February 10 episode of Raw, after losing a tag team match to the Street Profits, Moss turned on Rawley and pinned him to win the 24/7 Championship. On March 22, Moss lost the title to R-Truth while out for a jog, ending his reign at 41 days.
