Worrall's breakout came in the 2015–16 Sheffield Shield season and BBL05. He recorded his first 5 wicket haul in first-class cricket when he took figures of 5/69 against Victoria in the first innings. He followed this up in the second innings with three more wickets as the Redbacks went on to win by 8 wickets. He made headlines at the end of BBL|05 when, after starting the season outside of the Melbourne Stars' squad, he was brought into the team because other members of the team's pace attack were called up to play for Australia. In the final match of the regular season he took figures of 3/15 against the Perth Scorchers to help guarantee the Stars a home semi-final, a performance that David Hussey described as "world-class". He followed this up in the semi-final, also against the Scorchers, by taking 3/25 in another win. His form continued to improve over the rest of the Sheffield Shield season, with career-best figures of 6/96 against Victoria in the Sheffield Shield final in the absence of fellow Redbacks fast bowler Chadd Sayers. He finished the season as the second-highest wicket taker of the Sheffield Shield, with 44 wickets at an average of 26.18, and as a result he was named by the South Australian Cricket Association as the most improved player for the 2015–16 season, having gone from a fringe member of the squad to one of the key members of the South Australian pace attack.
