 In 2018, Denly joined the Sydney Sixers as a replacement for Jason Roy when he was selected by the national team in the 2017-18 Big Bash League season.He performed well in his four games, scoring 146 runs at an average of 73.00 with a top score of 72 not out.He was player of the match in the Sixers final match of the tournament against Melbourne Stars, making 72 runs from 45 balls and taking one wicket.