Sydney are facing up to being without Mitchell Prentice (red carded) while Dez Geraldi and Alex Brosque are both facing bans after yellows.

Speaking after the 3-2 defeat, Kosmina said: "I'm pretty disappointed because we talked about it enough, they were told enough, it was stupid, stupid.

"Dezy (Giraldi)was maybe a bit unlucky that he gave the penalty away, it was fairly soft, but he didn't have to keep chasing the referee because he knows what the rules are. He wanted a chance in the A-League, he's got it and he's blown it, basically.

"Brosquey was silly. He scored a great goal but took the edge off that by getting himself booked for approaching the referee.

"Mitchell Prentice's was just dumb, really dumb. Why? I haven't got a clue. There's no chance of winning that ball.

"The team-mates pay the price for stupidity, the club suffers because of players stupidity and maybe these guys have to learn a hard lesson?"

A striker shortage is now a real issue for Kosmina with both John Aloisi and Brendon Santalab injured. He said: "Chris Payne will probably be available. Might be a nice debut in the A-League for a 17-year-old kid."