The injury to Melbourne Victory defender Michael Thwaite is worse than first expected after he hobbled off the training track yesterday. For tonight's clash with Adelaide United, U20 Australian representative Seb Ryall will be called upon in a time of need for coach Ernie Merrick who is certain the young right back can hold his own.

Speaking to the Herald Sun, Merrick said, "Sebastian has just been a fantastic young player for us.

"He's mature beyond his years. He plays so well with Kevin (Muscat) and Rody (Vargas), and Sebastian's back to full fitness.

"He only dropped out of the squad due to his commitments with under-20s and he's back."

Socceroos squad player Thwaite hurt his ankle in the 5-0 win over the Newcastle Jets two weeks ago and looked to be available until he aggravated the injury in yesterday's training session.

Victory will also be without Costa Rican Jose Luiz Lopez who has been on international duty, but apart from that the starting line-up will stay as it was in the round 3 win.

Adelaide welcomes Brazilian import Diego for his first A-League appearance but will be without countryman Alemao who is sidelined for two weeks with a groin injury.