Sean James Spencer (born May 29, 1975) is a former American professional relief pitcher for the Seattle Mariners and Montreal Expos of Major League Baseball (MLB).

[2] He was selected by his hometown Seattle Mariners in the 40th round of the 1996 Major League Baseball draft.

He made his major league debut with the Mariners on May 6, 1999, pitching 1/3 of an inning and giving up 2 earned runs against the Cleveland Indians.

On August 10, 2000, Spencer was announced as the first of two PTBNLs traded to the Montreal Expos for Chris Widger.

This biographical article relating to an American baseball pitcher born in the 1970s is a stub.