Chambers' return to athletics took an unusual turn when he confirmed in March 2008 that he had joined English rugby league team Castleford Tigers on trial; a move which surprised and angered in equal measure given the fact he had never played the sport before. The Rugby Football League did not object to the move, in spite of his drug-damaged reputation, but stated much improvement was needed prior to any appearance for Castleford in the Super League competition. At a rugby press conference, Chambers expressed a desire to compete in the Beijing Olympics, casting doubt on his dedication to his new career. Chambers officially registered as a player with the Rugby Football League, and Martin Offiah declared that he was prepared to mentor Chambers. He completed training with the Castleford Tigers first-team squad and made his début in a reserve game against York City Knights, but Castleford announced that they would not be offering him a contract.