McGrattan made his first appearance for the team during the 1992 championship and quickly became a regular player until his retirement at the end of the 2004 championship. At club level McGrattan played with Portaferry, winning seven county championship winners" medals during a club career that spanned three decades.
Ulster Senior Hurling Championship (3) 1992 1995 1997 National Hurling League Division 2 (1) 2004 Ulster Under-21 Hurling Championship (1) 1990 Ulster Minor Hurling Championship (1) 1989 Ulster Minor Hurling Championship (1) 1989 Antrim Senior Hurling League (2) 2002 2003 Down Senior Hurling Championship (7) 1989 1991 1996 2000 2001 2002 2006.
