Western United look likely to be without captain Alessandro Diamanti for around two weeks after the playmaker limped off during their 3-0 A-League win over Central Coast Mariners.
Diamanti limped off 27 minutes into the game after a challenge from Daniel De Silva and was substituted three minutes later.
Coach Mark Rudan said the challenge was "innocuous" but he believed his captain had suffered an ankle or foot injury that could sideline him for a "couple of weeks" but hadn't spoken to United's medical staff.
"But he's a tough character - he hasn't missed one training session since pre-season started," Rudan said.
"He loves to train, he's a great pro, so for him to go down - and he gets hit quite a lot, not just in the games that you watch on weekends but at training as well."
Rudan said he expected the playmaker - who had played every minute of United's previous 13 games - to miss next Sunday's clash with Adelaide United, while there is a six-day turnaround to the trip to Newcastle.
"He (Diamanti) said he treaded and went to play the ball and felt the kick as well come in a little bit late," he said.
"It's not his knee - it's his ankle I think, or his foot."
Rudan praised the work of energetic young midfielder Max Burgess, who started the game brilliantly then replaced Diamanti with aplomb.
"I thought before Diamanti came off he was the star attraction," he said.
"I thought he was fantastic."