After questions of whether or not the Brazilian was eligible in United's 3-0 win over Persipura, the Australian side is not risking a potential challenge by bringing him along
The 32-year-old veteran participated in last month's play-off match against Indonesia's Persipura, but questions emerged after the 3-0 United victory over whether or not the Brazilian was eligible to play, having been sent off in the club's last ACL match in 2010 against Jeonbuk Motors.
Two weeks after the controversy arose, Australia's The Advertiser reported on Friday that the AFC has sent a disciplinary letter to the club and the Australian Football Federation (FFA) to be made public after both organisations have signed off on its contents.
"The club is simply not prepared [to risk a] potential challenge by Bunyodkor of any result it may achieve on Tuesday night," media manager Nic Kerber said in a statement.
"The AFC 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, by a club that Adelaide United has enormous respect and regard for."
Meanwhile, the statement went on to note that Cassio is expected to be available for their March 20 match against Japan's Gamba Osaka, who beat United in 2008 to win that year's ACL title.