Loss of form and a series of off-field controversies led to him being traded to St Kilda at the end of the 2006 season, having played total of 129 games for West Coast.

West Coast led at every break before being defeated by 13 points by North Melbourne, who went on to play St Kilda in the Preliminary Final.

[3] However, he was then limited by chronic knee injuries, and played 18 games in the next three seasons with the Eagles with Dean Cox becoming the leading ruckman in the AFL competition.

In May 2005, Gardiner and then West Coast teammate Ben Cousins were criticised for involvement with a group of alleged Perth crime figures.

[7] Gardiner's alleged off-field lifestyle issues were often seen as detrimental to the West Coast playing group and, in February 2006, in the midst of the Ben Cousins booze bus incident, he was dropped to the Western Australian Football League side Claremont indefinitely on grounds of poor performance and poor off field behaviour.

On 18 July 2006, Gardiner's playing contract was suspended indefinitely and he was fined $5,000[9] following his involvement in a traffic accident in the Perth suburb of Scarborough.

While he escaped the accident with only minor injuries, West Coast Eagles chief executive Trevor Nisbett said that it was highly unlikely the club would renew his contract at the end of the year.

[9] With Michael Gardiner's football career in limbo due to his effective sacking by the West Coast Eagles, speculation linked him with a trade to a Victorian-based club, with St Kilda or Carlton touted as the most likely destination for the ruckman.

Due to his gradual recovery process from obvious injuries and their referral effects, Gardiner was unable to play any competitive AFL football during the 2007 season.

[11] Michael Gardiner started his St Kilda FC playing career by competing in the Saints team that won the 2008 National Australia Bank Cup Premiership.

His attitude and effort in training, combined with the glimpses of form and class he showed in his handful of games warranted him being retained by St Kilda FC, whose season ended in the Preliminary Final.

[16][17] Gardiner played his 150th game of AFL football in the Saints Round 13 match against Richmond, a remarkable milestone for a player who had battled persistent injuries, before being traded by the West Coast Eagles in 2006.

[19] Gardiner would receive 3 Brownlow Medal votes in recognition of his performance as best player on ground against the Cats, which St Kilda won by 6 points.

[15] He combined his aggression and mobility around the ground with masterful ruck performances, recording a top three finish in the competition for hit-outs to advantage.

During the first half, Gardiner sustained a hamstring strain which effectively ended his season, restricted to the interchange bench for the remainder for the game.

[22] Hampered by persistent injuries throughout the season, Gardiner was only able to play in one match – the round 24 victory against Carlton which secured finals football for the Saints.