Star Wellington striker Oskar Zawada is set to spend around four weeks on the sidelines due to a thigh injury that required draining.
Zawada scored four goals in the first four games of the A-League Men season before being sidelined by a groin injury.
The former Poland youth international returned for the 1-0 win over Western United, but suffered a heavy knock to his thigh in the shock 3-0 loss to Newcastle on December 9.
Zawada was absent for Monday's 3-0 win over Macarthur and will also miss Saturday's home clash with Western Sydney as well as matches against Sydney FC and Adelaide United, barring a quicker-than-expected recovery.
"He had some leg bleeding in the contusion. At the moment, we're not quite sure the full extent," Phoenix coach Giancarlo Italiano said on Friday.
"It might be a grade-three tear, so he might be out for potentially four weeks.
"We'll find out a little bit later in the week. Hopefully early next week we'll see how his injury settles down.
"He had some fluid drained out of his thigh.
"It's progressing better than what we thought, but at this stage it's still early to make a call (of exact time line)."
Zawada's absence is a big blow to the high-flying Phoenix, who enter the current round on top of the ladder.
Western Sydney (15 points) are just two points further adrift in third place, and Italiano is expecting a stern test despite having the benefit of home-ground advantage.
"For us, we don't take them lightly," Italiano said.
"They've got a lot of good, young, energetic players.
"I'm a big fan of (Nicolas) Milanovic. I think he's quite effective around the box.
"(Marcus) Antonsson for me is very clinical, he's very good out and out nine.
"And the other import (Jorrit) Hendrix is very good on the ball.
"But we're at home. Our mentality is we're going to try to play our football and try to play as best as we can."
Italiano, who spent time as Sydney FC youth coach, was happy to see former Sky Blues coach Steve Corica handed the reins of expansion side Auckland, who will enter the competition next season.
"Its a good appointment. I've known him for a long time. He gave me my opportunity at Sydney, so I'm forever indebted to him," Italiano said.
"He's a good guy. And I think if you're going to start a franchise - his CV is the best in the A-League. Three titles and an Australia Cup.
"He's done really well. It's a good acquisition for them."
