The 31-year-old O'Bree played 246 games for the Pies, but this year has struggled with injury and has managed just six matches, the last one being the round 10 loss to the Brisbane Lions.
Rusling has played just one AFL game in the past three seasons, with injury cruelling his career.
O'Bree's consistency across his career was shown in his Copeland Trophy polling - he finished top five three times, and top 10 another four times, along with winning the Darren Millane (best clubman) award in 2006.
He was taken by the Brisbane Lions with pick 10 in the 1997 national draft, and played there for two seasons before heading to the Pies as the first selection in the 2000 pre-season draft, and is one of a select band of just 30 Magpies players to have notched up 200 VFL/AFL games.
Coach Mick Malthouse said he had enjoyed being part of O'Bree's career.
"I have been very impressed with him as a bloke. I think he has a fantastic football brain and used every ounce of his energy and body to get the best out of himself," he told collingwoodfc.com.au.
"He had an appearance of a very quiet person but I can't remember the number of players who would come up to me after games or during training to tell me that Shane O'Bree's advice and encouragement was outstanding."
Rusling was selected with pick 23 in the 2003 national draft, but played just 17 games, with six in 2005 his best return for a season.
Shoulder injuries were the main problem for the 23-year-old from Adelaide, although he did manage to play three finals in 2007.
He played seven VFL matches last year, and only a handful this season.
