Warner was selected in the 17th round of the 1991 Major League Baseball Draft after graduating from the University of Wyoming.

He threw and batted right-handed, stood 6 feet 3 inches (1.91 m) tall and weighed 185 pounds (84 kg).

[1] In 2000, Warner retired as a player and spent the season as the batting practice pitcher for the Major League Cardinals.

On December 10, 2014, Warner was named the Cardinals' roving minor league infield coordinator and was replaced as manager of the Redbirds by Mike Shildt.

[2] Midway through the 2017 season, the Cardinals promoted Warner to the big league staff in a general coaching role.