FORMER Carlton coach Brett Ratten will be plotting against the Blues next year after joining rival AFL club Hawthorn as an assistant coach.

Ratten, a Carlton premiership player and captain, coached the Blues from part-way through 2007 until the end of this year's season, when he was replaced by Mick Malthouse.

The move comes after Hawks assistant Leon Cameron joined Greater Western Sydney under a plan to succeed Giants head coach Kevin Sheedy.

''Brett is an excellent addition to our coaching line-up and will bring a great deal of experience and coaching nous to our club,'' Hawthorn coach Alastair Clarkson said. Ratten will start in November.

Former Brisbane Lions and Collingwood player and Gold Coast assistant Shane O'Bree has joined Geelong as an assistant coach.