Youngsters Steele Sidebottom and Ben Reid have also put pen to paper, each signing for a further two years.
Didak, who was taken with the third pick in the 2000 NAB AFL Draft, won the club's best and fairest award in 2006, and was expected to win his second in 2008 before a club-imposed suspension saw him miss the final six games of the year.
He has played 174 games already, and has 244 often-amazing goals to his credit, including a cracker on Saturday against Richmond.
Sidebottom was drafted from the Murray Bushrangers with the 11th pick in 2008, and has quickly established himself in the side. He played 11 games in his first year, and has missed just one this season, kicking 16 goals.
Reid has taken a little longer to develop after being picked up in 2006 at number eight. Initially groomed as a forward, he showed good signs when played as a defender, and has grabbed the opportunity, playing 14 games this year and being nominated for the NAB AFL Rising Star Award in round 12.
