Borussia Dortmund defender Sokratis Papastathopoulos has added to the club's growing injury worries after being substituted only seven minutes into his country's 2-0 World Cup qualifying win in Estonia.
Centre-back Sokratis, who has played the full 90 minutes in all 10 of his side's competitive matches this season, now seems likely to miss the clash with Hertha Berlin on Friday after suffering an apparent muscle injury.
Earlier on Monday, Polish international Lukasz Piszczek left the Polanmd squad ahead of the qualifier against Armenia with knee problems.
But Jakub Kwiatkowski, the Poland team's media officer, wrote on Twitter: "The injury is not serious. Lukasz will return to his club for further examination."
Also on Monday, Raphael Guerreiro missed Portugal's win over Faroe Islands.
Centre-back Marc Bartra is working on his comeback from a groin injury, while at the weekend it was reported that midfielder Gonzalo Castro could be out for up to four weeks, also with groin problems.