Guerrero was signed by the Montreal Expos as an unsigned amateur free agent, on March 1, 1993. He advanced quickly through the Expos’ Minor League Baseball (MiLB) farm system, making his MLB debut, on September 19, 1996. That night, Guerrero went 1 for 5 at the plate; his first big league hit, a single to center field, came against Atlanta Braves starting pitcher Steve Avery, in the top of the fourth inning, at Atlanta–Fulton County Stadium. Two nights later, on September 21, 1996, Braves closer Mark Wohlers yielded Guerrero's first career home run (HR) — a ninth-inning blast that capped Montreal's scoring, in a 5-4 loss. That contest is also significant, in that it marks Guerrero's first multi-hit game.