Josh Risdon's nightmare 2020/21 season may be over, with Western United coach Mark Rudan confirming initial scans on the fringe Socceroos' latest injury are concerning.

Risdon was making just his third appearance of the season in Monday's 2-0 win over Newcastle Jets at AAMI Park when he limped off after 21 minutes following a challenge with Apostolos Stamatelopoulos.

Rudan said on Wednesday the 28-year-old was facing at least a month on the sidelines.

"First set of scans, not looking good ... there's a second set of scans he needs to do now but it's not looking good initially," Rudan said. "Best-case scenario is two-to-three weeks.

"Worst-case scenario is a lot worse than that. Season-ending."

The news is devastating for the fullback who had been sidelined since late December with a tibia injury.

Rudan said it was a bitter pill for everyone at the club to swallow, especially given their excitement at Risdon's return in time for this season's finals.

""It's been a tough one for Josh," Rudan said.

"We all know just how important he is to our football club and our team. Finally gets himself back in there and an innocuous challenge by his good friend Stammo puts him out now for at least a month, maybe longer."

Risdon isn't the only injury concern for Rudan heading into Friday's clash with Adelaide United at Coopers Stadium.

Dalibor Markovic has undergone scans after appearing to roll his ankle late in the win over the Jets which Rudan said are "not looking good either" while Luke Duzel is also unlikely to travel to South Australia after picking up a groin niggle in the warm-up before Monday's game.

Friday's game with the Reds is the first of four straight on the road for sixth-placed Western in a crucial period for their finals hopes.