Germany midfielder Dietmar Hamann and South Korea striker Ahn Jung-hwan are doubtful for Tuesday's World Cup semifinal - the first in the 72-year history of the tournament to feature an Asian side.
Combative midfielder Hamann twisted a ligament in his right knee in Friday's 1-0 quarter-final win over the United States.
Hamann took part in the first 15 minutes of a final training session on Monday at the Seoul stadium where the semi-final will be played, but pulled out early.
"He (Hamann) is extremely important to the team and it would be a big blow if he couldn't make it but he will only play if he's 100 percent fit," Germany coach Rudi Voeller said.
If the 28-year-old does not recover, Voeller will probably hand his defensive central midfield role to Jens Jeremies.
Ahn, who scored South Korea's 'golden goal' winner against Italy in the second round, sprained an ankle in the quarter-final penalties win over Spain. The most likely replacement is Hwang Sun-hong, more of a target man than the lightly built Ahn.
The co-hosts, without a match win in five previous finals, have exceeded all expectations by becoming the first Asian team to reach the last four. They now face a team who have reached the semifinals on nine occasions - going through six times.
The two sides met in the 1994 World Cup in the U.S. with the Germans coming out 3-2 winners.
In the past month the Koreans have put aside any feeling of inferiority towards European opposition with wins over Poland, Portugal, Italy and Spain.
"We don't fear European teams any more. We will go out and give our best again," said captain Hong Myung-bo.
After the Koreans gained from controversial refereeing errors in their last two games, the pressure will be on Swiss official Urs Meier to deliver a faultless performance.
The other semifinal between Brazil and Turkey takes place on Wednesday in Saitama, Japan.
Germany (3-5-2): 1-Oliver Kahn; 21-Christoph Metzelder, 15-Sebastian Kehl, 2-Thomas Linke; 22-Torsten Frings, 19-Bernd Schneider, 8-Dietmar Hamann (or 16-Jens Jeremies), 13-Michael Ballack, 6-Christian Ziege; 11-Miroslav Klose, 7-Oliver Neuville
South Korea (3-5-2): 1-Lee Woon-jae; 4-Choi Jin-cheul, 20-Hong Myung-bo, 7-Kim Tae-young; 21-Park Ji-sung, 6-Yoo Sang-chul, 22-Song Chong-gug, 10-Lee Young-pyo, 13-Lee Eul-yong; 19-Ahn Jung-hwan, 9-Seol Ki-hyeon.
Referee: Urs Meier (Switzerland)
Frederic Arnault (France)
Evzen Amler (Czech Republic)