His college baseball coach at Orange Coast College Mike Mayne explained to The Times in 1990 O'Halloran's smaller size helped him make his decision to play baseball over hockey.
"When he got into the higher levels of hockey, he was getting his block knocked off," Mayne told The Times. "He figured that even catching would be safer than playing hockey."
O'Halloran's choice eventually paid off in the majors. His major league career consisted of 12 games spent with the Marlins in 1994. He played as a pro over eight seasons, but his big league time remained confined to that one season with Florida.
O'Halloran's career began in 1988, taken by the Blue Jays in the 32nd round of the draft out of Orange Coast.
O'Halloran joined the Blue Jays after playing on the 1988 Canadian Olympic baseball team.
He recalled in May 1990 to The St. Petersburg Times telling his family outside of Toronto of his hopes in baseball. Everyone laughed.
"This winter I even found a journal I had kept where I had written what I said and people told me, that's great Greg. Hope you do it. But nobody took me seriously," O'Halloran told The Times.
O'Halloran started with the Blue Jays at short-season St. Catharines in 1989. The catcher hit .283 over 69 games. He hit five home runs.
He moved to high-A Dunedin for 1990. He hit .284 over 121 games. He made AA Knoxville in 1991 and again in 1992. He made AAA Syracuse for 1993. He hit .267 over 109 games, but he didn't make Toronto.
O'Halloran moved to the Marlins for 1994 and then he made the majors. He debuted May 16 and played his last game Aug. 6. He scored the winning run of a May game after getting his first hit.
He played the balance of that year at AA Portland. He then played 1995 with the Cubs briefly at AAA Iowa and then at independent Duluth-Superior. He finished out his career in 1996 in Mexico and 1997 in Taiwan.
He served as a scout with the Major League Baseball Scouting Bureau and coached with Team Canada in the World Baseball Classic in 2006 and 2009. In 2016, he joined Terriers Baseball as a coach.
- St. Petersburg Times, May 7, 1990: O'Halloran is right at home with Blue Jays
- Los Angeles Times, July 30, 1990: Canada's O'Halloran Switches Sticks in Pursuit of a Professional Career
Players/Coaches Featured: 2,842
Made the Majors:1,071-37.7%-X
Never Made Majors:1,771-62.3%
5+ Seasons in the Majors: 444
10+ Seasons in the Minors:267