He quickly established himself as a fixture at lock for the province, and by 2005 was one of the standout players in the provincial championship, forming a dynamic partnership with James Ryan.

Although injuries and international duty have limited his availability for Otago, he remained a fixture in the squad, captaining the team for a stretch in 2007 in place of an injured Craig Newby.

Due to a shoulder injury and his time with the All Blacks, Donnelly made only a single appearance for Otago in the 2010 ITM Cup.

However, in the 2011 ITM Cup he appeared in every game, serving as team captain for the majority of the season following an injury to Eben Joubert.

Back healthy in 2011, he found himself in an unfamiliar position coming off the bench as the strong play of Josh Bekhuis and Jarrad Hoeata kept him out of the starting line-up.