Fremantle coach Justin Longmuir has spoken about the recent sickness that has hit the AFL club, believing it was a big reason behind a quiet game by Patrick Voss against the Western Bulldogs last week.

Voss lacked his usual "Prancing Pony'' presence in last week's 12-point win over the Bulldogs, with the key forward held scoreless from just five disposals.

It came just a week after he was a last-minute scratching from the win over Carlton because of sickness.

It is believed Voss had been vomiting in the lead-up to the Blues clash, but still tried everything he could to get up for the game.

Voss kicked 37.23 from 20 games last season, but has returned just 7.12 from seven matches this year.

He was also fined earlier this season for taunting Melbourne defender Harrison Petty.

Despite Voss's quieter returns this season, Fremantle (7-1) are riding high on a seven-match winning run heading into Thursday night's blockbuster against Hawthorn (6-1-1) in Perth.

Longmuir isn't worried about Voss's form, saying he's confident the quiet display against the Bulldogs was just down to the recent illness.

"He missed the week before with sickness, and maybe that lingered a little bit into last week's game," Longmuir said on Tuesday.

"But previously it's probably been a little bit of inaccuracy which has cost him (this season).

"I'm happy with the way he's working with the other talls, and I think they're pretty formidable opponents."

Defender Judd McVee missed the win over the Bulldogs with sickness, and there have been a number of other Dockers players who have fallen ill in recent weeks.

So far, only Voss and McVee have missed games because of it.

"We've had a little bit of sickness through the camp," Longmuir said.

"Some guys have got it a lot worse than others, and it has lingered.

"What made last week's win even more pleasing and (why I'm) more proud of the group is we had four or five guys miss training and miss certain parts of prep, and those guys went out and played their role really well.

"So there's been a little bit of a distraction. It's a bit of a management thing to try and keep them away from the rest of the group."

Longmuir is optimistic the team is over the recent illness hit, and is embracing the challenge of taking on a Hawthorn outfit looking to bounce back from last week's draw with Collingwood.