Son Heung-min was named in South Korea's squad on Saturday for the Qatar World Cup but it remains to be seen if he will play after a serious facial injury.
South Korea's captain and talisman suffered a fracture around his left eye during a Champions League match for Tottenham and then had surgery last week.
"We are in contact with him and Tottenham's medical department," said South Korea's Portuguese coach Paulo Bento as he named his squad.
"About the exact day he can train with the team, we don't have that information," he said.
"We need to wait, we need to analyse day by day his situation.
"We have time to decide. The most important (thing is that), he recovers as well as possible, he feels comfortable and then we will take the final decision."
Bento named a 27th player, forward Oh Hyeon-gyu, who will train with the team in Qatar and could replace Son if he does not make it.
South Korea's opening match is against Uruguay on November 24.
Son, who has scored 35 goals in 106 international appearances, wrote on social media this week that "I can't wait to represent our beautiful country, see you soon".
South Korea also play Ghana and Portugal in Group H.
A South Korean team missing Son and other Europe-based players beat Iceland 1-0 in a home friendly on Friday.
Goalkeepers: Kim Seung-gyu (Al-Shabab/KSA), Song Bum-keun (Jeonbuk Motors), Jo Hyeon-woo (Ulsan)
Defenders: Kwon Kyung-won (Gamba Osaka/JPN), Kim Moon-hwan (Jeonbuk Motors), Kim Min-jae (Napoli/ITA) Kim Young-gwon (Ulsan), Kim Jin-su (Jeonbuk Motors), Kim Tae-hwan (Ulsan), Yoon Jong-gyu (FC Seoul), Cho Yu-min (Daejeon Hana Citizen), Hong Chul (Daegu FC)
Midfielders: Kwon Chang-hoon (Gimcheon Sangmu), Na Sang-ho (FC Seoul), Paik Seung-ho (Jeonbuk Motors), Lee Kang-in (Real Mallorca/ESP), Lee Jae-sung (Mainz/GER), Jeong Woo-yeong (Freiburg/GER), Hwang In-beom (Olympiakos/GRE), Hwang Hee-chan (Wolverhampton Wanderers/ENG), Song Min-kyu (Jeonbuk Motors), Son Jun-ho (Shandong Taishan/CHN), Na Sang-ho (FC Seoul)
Forwards: Son Heung-min (Tottenham Hotspur/ENG), Cho Gue-sung (Jeonbuk Motors), Hwang Ui-jo (Olympiakos/GRE)