Gregory Joseph O'Halloran
- Bats Left, Throws Right
- Height 6' 2", Weight 205 lb.
- School Orange Coast Junior College
- Debut May 16, 1994
- Final Game August 6, 1994
- Born May 21, 1968 in Toronto, ON CAN
Greg O'Halloran hit .300/.300/.533 as the catcher for Team Canada in the 1988 Baseball World Cup. On an explosive offense, he actually managed to have a lower average, OBP and slugging percentage than the team totals. Oddly enough, this was also the case for one of the other two future major league position players on the team - Rob Butler barely was over in OBP and average while trailing in slugging - as those who stalled in the minors outperformed their future MLB counterparts.