Gubanich's primary position was catcher, though he also made two appearances as a designated hitter and played seven innings at third base.

On August 5, Gubanich was dealt to the Colorado Rockies as the player to be named later in an April 23 trade for infielder Jeff Huson.

He appeared in 86 games with the Las Vegas Stars of the Pacific Coast League, San Diego's AAA affiliate, and hit .291 with 19 home runs and 70 RBI.

He made his Major League Baseball debut with the Red Sox on April 16, 1999 against the Tampa Bay Devil Rays as a defensive replacement for Reggie Jefferson, who had pinch-hit for Boston catcher Jason Varitek.

[3] Despite his historic slam, Gubanich's time in the big leagues was short-lived as he appeared in just 15 more games with the Red Sox and was released in October 1999.