Complex sentence: Duffy joined Harlequins from Connacht in the summer of 2003, having refused an offer from Munster after they had signed Christian Cullen, and made his league debut in the Zurich Premiership game against Rotherham Titans on 20 September that year.
Split into simpler sentences: Duffy joined Harlequins from Connacht in the summer of 2003, having refused an offer from Munster after they had signed Christian Cullen. He made his league debut for the Premiership side in a game against Rotherham Titans on 20 September that year.