He was not at practice with the Chiefs on Tuesday as he battles a back injury and his No 9 jersey was worn by new signing JuJu Smith-Schuster earlier this week.
It remains to be seen what this disappointment means for the Welshman’s long-term future in the sport.
Rees-Zammit had cemented himself as a superstar in rugby and his family have been out to Kansas City to support him during preseason training camp.
But he always faced an uphill task to make the team in his rookie season.
Though the Welshman has long dreamed of a career in the NFL, he had never played a game of American football before joining the NFL’s International Player Pathway in January.
He was put through a 10-week boot camp before impressing scouts at a ‘pro day’. Rees-Zammit received interest from nearly half of the 32 teams in the NFL.
He chose the Chiefs and played in all three preseason games – against the Jaguars, the Lions and Bears – where he was used as a running back, a receiver, a kicker and a kick returner.
It was long felt that Rees-Zammit’s hopes of making the roster rested on his impact on special teams. His performances improved throughout preseason and he received praise from coaches and teammates including quarterback Patrick Mahomes.
‘I’m not going to be the best player in the world overnight… I’d never played this sport before one week ago,’ Rees Zammit said after facing the Lions.
‘People try and put me down… but I’m going to continue to work really hard every day and learn as much as I can.’
Players on the practice squad can be signed by other teams or called up three times during the regular season.
Typically, though, they will help prepare the starters by imitating opposition players during practices.
