Adelaide United playmaker Dario Vidosic's recurrence of a hamstring injury is bad luck rather than bad management, Reds coach John Kosmina says.Vidosic will miss Friday night's A-League fixture against Western Sydney Wanderers after limping off at Adelaide's match-eve training session.Kosmina was uncertain how long Vidosic will be sidelined by the latest flare-up of an injury which has troubled the gifted attacker for the past year."We have got to get it fixed ... I want to make sure he is fit before we use him again, it's as simple as that," Kosmina told reporters on Thursday."We will get it cleared up - it has recurred, so we have got to look at why it's recurring."Vidosic was troubled by hamstring soreness pre-season but played in Adelaide's failed Asian Champions League quarter-finals against Uzbek club Bunyodkor, which ended last Wednesday.The No.10 then scored the opening goal in Adelaide's 2-0 win against Newcastle in their A-League season opener last Sunday.Despite the workload on the fringe Socceroo, Kosmina rejected mismanagement as the cause of Vidosic's latest setback."He wasn't rushed back too quick ... he had two weeks of preparation," he said."He played 120 minutes in Bunyodkor and he played 90 minutes in Newcastle last week, so if there was a problem, it would have shown up before then."... One of things we are always wary of, is getting him up for Newcastle wasn't difficult, but getting him up for this game would be difficult because of the travel and the fatigue."Most of them (Adelaide players) have slept a hell of a lot more than they would usually, we have only had two training sessions and yesterday was light, today was a lot longer than we normally would go the day before the game but we figured they have got enough gas in their tank."But the other side of it is, if you have got a little niggle and you're not training, they tend to show up later rather than sooner and unfortunately it's too late for Dario."