The Phoenix sit top of the table and were looking forward to regaining their marquee man for the run-in, which begins on Sunday against Brisbane Roar.

But coach Giancarlo Italiano on Thursday revealed Zawada is struggling from the after-affects of a knock suffered in round seven against Newcastle.

"They've done another scan and they found ... a bit of a growth," he said.

"We'll see in the next week or two whether or not he can actually continue on this year.

"At the moment I'd probably have him ruled out for the rest of the season."

The injury is an odd one, with new bone growing in Zawada's thigh as his body attempted to heal from the original trauma.

The Polish marquee is a huge loss for Wellington as they chase the first trophy in the club's 17-season history.

Zawada is one of the league's most-prolific strikers, with 20 goals in 35 A-League appearances for Wellington across two seasons - a tally expected to attract interest from clubs in Europe.

This campaign, he's endured leg and groin issues - restricting him to just 535 minutes and five starts, the most recent coming in December when he suffered the leg injury.

The last time Brisbane visited the Kiwi capital, Zawada put in a stunning shift, scoring a hat-trick in a 5-2 win.

Riddled with absences, Wellington are playing like a zombie that just won't die: continuing at the top of the table despite fielding academy products with senior players missing.

"I'll be concerned when we don't have 11 players we can put on the park," Italiano said.

"We've gone through this all year. At the beginning of the year, everyone was talking about a lack of depth.

"The boys have answered that well ... we've had injuries all year and we've had to makeshift players into different positions."

This weekend, Italiano's biggest issues are at the back.

Tim Payne and Isaac Hughes are missing with hamstring injuries suffered in their last-out 2-1 win over Sydney FC at Eden Park in Auckland.

Finn Surman could also miss after the centre-back copped a boot to the head in All Whites training. Italiano said the defender has an infection after five stitches.

Given all that, the Roar - sitting eighth and needing a win to stay in contention for finals - may be crossing the Tasman at a good time.

Wellington sent six players on international duty with New Zealand in Egypt this week, where the All Whites lost friendlies to the hosts and Tunisia.

While Surman returned early, Kosta Barbarouses, Ben Old, Alex Rufer, Lukas Kelly-Heald and Alex Paulsen are still making their way back.

"They're all on business class, which is an advantage," Italiano said.

"I'm not complaining because ... it's a really good experience."

Australian Associated Press