Rees-Zammit quit Welsh rugby on the eve of this year’s Six Nations tournament to pursue a career in the NFL in America.
He is part of the 2024 IPP, a 10-week crash course designed to teach players the required skills to succeed in the NFL.
The ex-Gloucester back – who won 32 caps for Wales, scoring 14 tries – showcased his skills at University of South Florida’s Pro Day this month, with scouts from all 32 NFL teams in attendance.
He is now vying to be selected for a team’s summer training squad before the new season – which begins in September.
The Kansas City Chiefs – who have won three of the past five Super Bowl titles – are among the latest to take an interest in the Welshman.
Led by quarterback Patrick Mahomes, the Chiefs defeated the San Francisco 49ers 25-22 in February to become the first side to retain the Super Bowl since the New England Patriots almost two decades ago (2004 and 2005).
The Broncos finished third in the AFC West last season – two spots below the Chiefs – with a record of eight wins and nine losses during the regular season.