Two-time winners Guangzhou Evergrande will have to do without star man Paulinho as the delayed Asian Champions League East returns this week with a heavy schedule of games played in "bubble" conditions in Qatar.
Fifteen teams will race through 33 matches in a little over two weeks to complete the group stage, suspended because of the coronavirus since early March, with eight teams then playing the knockout phase to decide who reaches the December 19 final.
Shanghai SIPG players, including former Chelsea midfielder Oscar, Asia's most expensive player, arrived in full hazmat suits, illustrating the challenges facing the tournament.
Qatar, the 2022 World Cup host, has already successfully staged the West zone competition, won by Iran's Persepolis who now await the East winner in the final.
But although Qatar was praised for its "smooth delivery," it wasn't trouble-free as defending champions Al Hilal were kicked out when an outbreak left them unable to field enough players.
Players and officials must be tested before departure and on arrival in Qatar, and will undergo further tests every three to six days.
"All players and officials will also be put under a bio-secure bubble which limits their movement only to the hotel, stadium and training sites," the Asian Football Confederation added.
All four Chinese teams are staying in the same hotel in Doha, with four floors each and separate dining areas.
Evergrande are one of three Chinese sides who are yet to play a match in the competition, which was halted after a handful of games eight months ago as the pandemic advanced.
Coach Fabio Cannavaro, the 2006 Italian World Cup-winning captain, will be hoping to make amends after Evergrande lost their Chinese Super League title to Jiangsu Suning last week.
But they will have to do without Paulinho, the former Barcelona and Tottenham Hotspur midfielder and their top scorer, who is out with a thigh injury.
Captain Zheng Zhi, 40, is also ruled out for Evergrande, who begin their campaign against South Korea's Suwon Samsung Bluewings on Sunday and also face Japan's Vissel Kobe in Group G.
The group has been cut to three teams after Malaysia refused to let Johor Darul Ta'zim leave the country over the pandemic.
In Group H, Shanghai SIPG play Sydney FC tomorrow before facing Jeonbuk Hyundai Motors, the 2006 and 2016 champions who are bidding for a trophy treble after winning the South Korean league and cup double.
SIPG have Brazilians Oscar and Hulk and Australia's Aaron Mooy at their disposal, but former West Ham forward Marko Arnautovic was left out after traveling for internationals with Austria.
Beijing Guoan will similarly be without Cedric Bakambu after the forward flew off to play for Congo in the Africa Cup of Nations.
China's football association urged its teams not to bring players who have been on international duty.
