Douglas goes under the knife
Douglas suffered the blow during Australia's World Cup Final against New Zealand.
The 26-year-old injured his knee when he fell awkwardly just 15 minutes in to the decider and took no further part in the match.
The bruising lock forward was hustled back to Australia from Ireland's Pro12 side Leinster in order to qualify to play for the Wallabies. The Reds signed him for 2016 and he is expected to play an important role in their Super Rugby campaign.
Following his surgery later this week, Douglas will continue his rehabilitation and return to play under the Reds medical and high performance staff.
Douglas was one of only eight Wallabies players to play in every match at World Cup, taking his career tally to 23 Test caps since making his debut for Australia in 2012.