Gehrig struggled to break into a powerful Eagles lineup during his first few years at the Western Australian club, but he stepped up in 1997 and won selection in the All-Australian team in a forward pocket.
West Coast received David Sierakowski and 2000 AFL draft selection number 18 (Daniel Kerr) from St Kilda in exchange for Gehrig.
After initially playing at full-back in his first year at his new club, Gehrig finished second in the St Kilda best and fairest award.
He switched to the full-forward position in 2003, and this move coincided with St Kilda's rise up the ladder, finishing 11th in 2003 and playing in finals matches in 2004, 2005 and 2006.
In the dying seconds of the match, Gehrig took a strong mark in St Kilda's forward line and kicked his 540th career goal, one of five that day, to secure the win.
[5] Gehrig was chaired off the ground by St Kilda players Nick Riewoldt and Justin Koschitzke, bare-chested after giving his famous number-nine jumper to a young female fan in the stands.
This option forced Gehrig onto the standard two-year draftees' contract, but allowed the club to redraft him without using an early pre-season draft selection.
Gehrig's subsequent return to the senior list was a precaution in case of injury to other players, though he did not play for the remainder of the season.
Gehrig, with Steven Lawrence and former Brisbane Lions captain Michael Voss, were all charged over a fight in a St Kilda hotel.