West Australian police have dropped one of the two charges against former West Coast Eagles star Ben Cousins which prompted the club to terminate his contract this week.

After being stopped by police for driving erratically in Perth on Tuesday morning, Cousins was charged with being in possession of a prohibited substance and refusing a blood test.

Cousins appeared before the Perth Magistrates Court on Thursday and after being granted a 90-day adjournment to allow him to travel to the United States for further treatment in a drug rehabilitation clinic, declared through his lawyer his determination to fight both of the charges against him.

On Friday the club released a statement that it had been informed by the West Australian police that the charge of being in possession of a prohibited substance had been dropped.

The club noted however that, "this does not change the club position or the decision made on Wednesday to terminate Ben's contract because of repeated and serious breaches to his agreement with the club".

When asked on Thursday what would happen if the charges against Cousins were dropped, AFL chief executive Andrew Demetriou noted that Cousins' contract was terminated because of an accumulation of events and a breach of the conditions in the contract governing his return to football.

"Whether the charge of being in possession of a prohibited substance (is dropped), I don’t think it matters," Demetriou said.

"The fact of the matter also is that he didn't co-operate with the police and really, that is just completely unacceptable, completely unacceptable."

The club said it wished Cousins well as he continues with his rehabilitation program.