Saturday night's AFL clash between Fremantle and North Melbourne will go ahead despite Perth's three-day lockdown, but crowds won't be allowed.
Perth and the Peel region will enter a snap lockdown from midnight WST after a man contracted COVID-19 while staying at Mercure Hotel Perth.
One of his close contacts that he stayed with after his hotel quarantine period has also tested positive to COVID-19.
Members of the public will be forced to wear masks from 6pm WST on Friday, with the lockdown due to end at midnight WST on Monday.
The Western Force's Super Rugby AU clash with the Queensland Reds at HBF Park on Friday night.
The Perth Wildcats' NBL clash with the Brisbane Bullets at Perth Arena can also go ahead on Friday night with full crowds, but attendees will have to wear masks.
The Force's clash begins at 5.45pm, meaning fans won't have to wear masks until the 15-minute mark of the match.
Even if no one else contracts the virus and the lockdown is lifted on Monday night, it's expected the restrictions will be eased in phases.
Optus Stadium recently had its capacity returned to 100 per cent, and it remains to be seen what restrictions will be placed on the venue next week.
West Coast are scheduled to play Fremantle on Sunday week in a match that would normally attract close to 60,000 fans.