Widnes Vikings have suspended Rangi Chase after the half-back tested positive for cocaine.
UK Anti-Doping and the Rugby Football League informed Super League club Widnes that Chase failed a drugs test following a 36-8 loss to Wakefield Trinity last month.
The former England international has been banned from playing for the Vikings and is also unable to train with the club.
A Widnes statement said: "The club fully respects this suspension and are currently reviewing this matter. There will be no further comment at this time."
Chase, Man of Steel in 2011, joined Widnes on a permanent deal last month after initially making a loan move from Castleford Tigers.
The New Zealand-born 31-year-old's has had a number of off-field issues in his career and retired before signing for Castleford last year.
Meanwhile, Catalans Dragons could launch an appeal after full-back Tony Gigot had his suspension increased back to two years.
Gigot was initially given a two-year ban in February after being found guilty of an "inappropriate exchange" with an anti-doping officer during a France training camp last October.
That was reduced to only three months in April, but the French Anti-Doping Agency has restored the punishment he was first given.
Catalans Dragons Chairman Bernard Guasch said in a statement: "The club is shocked by this decision. Tony Gigot underwent three anti-doping tests in six months and all of them were negative. The club will continue to support and protect Tony in this tough period. Our lawyer is studying the possibility of appealing this decision."