Adelaide United have left star left-back Cassio behind as they travel to Uzbekistan, fearing his presence may have put at risk their Asian Champions League (ACL) opener.

Cassio failed to serve a one-match suspension for being sent off in the Reds’ last ACL match, in 2010.

The Brazilian defender played in an ACL qualifier against Indonesia’s Perispura two weeks ago, which Adelaide won to advance into the lucrative tournament.

But with Cassio’s eligibility for Tuesday’s ACL opener against Bunyodkor in doubt, Adelaide opted for an cautious approach by leaving him out of their travelling party.

“The club is simply not prepared to put at risk of a potential challenge by Bunyodkor of any result it may achieve on Tuesday night,” United said in a statement on Friday.

“The Champions League is a highly prestigious tournament.

“And Adelaide United would never put at risk the high standing it holds in Asia as the most successful Australian club ever in the competition by playing Cassio and then risking a challenge, which in all likelihood would never be made.

“For this reason alone the club has decided to leave Cassio home.”

Adelaide United made the ACL final in 2008, and coach John Kosmina hopes the Asian adventure is a welcome retreat from the Reds’ A-League woes.

Adelaide lost 2-0 to Perth Glory on Thursday night and remain in ninth-spot in the domestic competition.

But Kosmina said player morale remained high entering the champions league.

“I think we’ll do all right. It’s just a matter of taking the right attitude into Asia,” Kosmina said.

“We will play a little bit differently and probably be a little bit more conservative, trying to find our feet.

“But we have got to look at this now as a new adventure.

“And it’s something exciting that a lot of blokes have never experienced before, myself included.

“So from that perspective, you go over there and enjoy it and try and get something out of it.”