Hamburg's Dutch captain Rafael van der Vaart is a major injury doubt for Sunday's Bundesliga clash at home to Hanover after damaging his ankle while on international duty.
The 30-year-old had to be helped off just before half-time in the Netherlands' goalless draw with Colombia in Amsterdam on Tuesday and Dutch coach Louis van Gaal said the injury was serious.
"Luckily, he hasn't broken or torn anything, but I don't think he'll be able to play at the weekend," said Van Gaal.
Van der Vaart is due to have an MRI scan in Hamburg and his club are waiting on the diagnosis ahead of the match against midtable Hanover.
With six goals in 12 Bundesliga games this season, an injury would be a significant blow to Hamburg's attack with only Germany Under-21 striker Pierre-Michel Lasogga, who has hit the net eight times in eight league games this season, having scored more goals for the Hanseatic side.
Hamburg, 14th in the league, have climbed out of the relegation places under ex-Dutch coach Bert van Marwijk, who replaced Thorsten Fink in September after a poor start to the season.