Germany head coach Joachim Low has confirmed that illness has severely limited Toni Kroos in training this week and could result in the Real Madrid midfielder being rested for Friday night's (10 November) friendly clash with England.
79-cap stalwart Kroos played 90 minutes for Real Madrid in their morale-boosting 3-0 La Liga victory over Las Palmas last weekend and subsequently joined up with Die Mannschaft's squad for a trip to Wembley Stadium and a home fixture against France in Cologne.
However, he later emerged as a doubt for that first match after reportedly missing training on Wednesday due to a stomach virus.
The 27-year-old was unable to participate fully in a subsequent session yesterday and Low could opt to leave him on the sidelines if he does not recover sufficiently before kick-off in northwest London.
"Toni Kroos was sick yesterday and only took part in the warm-up today," he told reporters at a pre-England press conference.
"I need to see how he feels today and talk with him. Maybe he will be rested if he doesn't feel at full fitness."
Muscle problems have already ruled Bayern Munich defender Jerome Boateng out of that England friendly, while Germany's opponents have now suffered no fewer than seven withdrawals after Stoke City goalkeeper Jack Butland broke a finger in training on Thursday.
Jordan Pickford, Ruben Loftus-Cheek and Tammy Abraham are all set to win their first senior caps as Gareth Southgate prepares to field the most inexperienced Three Lions side for 41 years, captained by 23-year-old Tottenham Hotspur midfielder Eric Dier.
Meanwhile, Real Madrid will hope that Kroos is able to shake off that bout of illness before their next domestic outing - the small matter of a Madrid derby against Atletico at the Wanda Metropolitano on Saturday 18 November.
Zinedine Zidane could welcome back Gareth Bale, Dani Carvajal and Keylor Navas for that high-profile fixture, while midfielder Mateo Kovacic has continued his recovery from a partial tear on the large tendon in his right adductor muscle by taking part in some light training sessions on his own this week.
Raphael Varane also looks set to be fit to face Atletico after missing the embarrassing 3-0 Champions League defeat to Tottenham and the aforementioned win over Las Palmas due to a hamstring issue that forced him off at half-time of the loss to Girona.
The injury-prone centre-back was called up to the France squad for meetings with Wales and Germany and Marca report that he is expected to play for Les Bleus in Saint-Denis on Friday after being permitted to train with the rest of his teammates following "strenuous medical tests".
Speaking about Varane earlier this week, France boss Didier Deschamps assured concerned Real that he would not take any risks with his fitness and insisted that the defender would continue to be be monitored throughout the week.
"He had a little problem last week and couldn't play last weekend," he said. "We will see his development in the next 72 hours but we won't be taking any risks. Is it a problem of time, not an big muscle problem."