The All Black and Crusader Zac Guildford is to undertake an intensive treatment programme to address what are being described as "personal issues".
The winger is under investigation by the New Zealand Rugby Union after an alcohol-fuelled altercation this month.
Rugby Union chief executive Steve Tew said Guildford was withdrawing indefinitely from the Crusaders rugby team to concentrate on resolving his personal issues.
Mr Tew said he was working with the Players Association and Guildford's manager to ensure the player gets the professional help he needs.
The nature of the treatment programme is not being disclosed.
Misconduct proceedings against Guildford are on hold, and Mr Tew said they would be addressed later.
Chief executive of the Rugby Players Association, Rob Nichol, said Guildford wanted to make the most of the opportunity for treatment and appreciated the support he was receiving.
Crusaders welcome Guildford's decision
The Crusaders rugby team is welcoming the decision by Guildford
Crusaders coach Todd Blackadder said he saw it as a positive step for Guildford in overcoming his illness.
He said it was too early to say how the withdrawal will affect the Crusaders.
Guildford has been involved in alcohol-fuelled incidents in the past including an attack on patrons at a bar in the Cook Islands.