Real Madrid star Toni Kroos has given Zinedine Zidane fresh concerns ahead of upcoming games against Getafe (14 October) and Tottenham Hotspur (17 October) after pulling out from the Germany squad with a rib injury.
The 27-year-old midfielder recently missed La Liga victories over Real Sociedad and Alaves, with Zidane revealing that he was having some discomfort in the ribs.
However, the midfielder still decided to join up with Germany for the final two World Cup qualifiers after he was able to play for Real Madrid in the games against Borussia Dortmund and Espanyol.
Kroos made Joachim Löw's starting line-up on Thursday night (5 October) as Germany confirmed their qualification for the World Cup 2018 with a comfortable 3-1 victory over Northern Ireland in Belfast.
The Real Madrid star played the full 90 minutes, but Germany have decided to release him from the final clash with Azerbaijan on Sunday (8 October) after confirming that he is still nursing a rib injury.
"World Champion Toni Kroos is set to miss this Sunday's final World Cup Qualifying Group game against Azerbaijan with a rib injury," the German national team confirmed through an official statement.
"The midfielder left the team hotel in Belfast on Friday morning and will now let the injury, which has also caused him to sit out games for his club Real Madrid recently, fully heal."
Meanwhile, manager Joachim Löw added: "We know what Toni can give us. When it comes down to it we can always rely on him. The deciding factor was that he is completely fit for next year and able to get through this season and build up his strength."
The decision could be only precautionary given that Germany have already booked a place in Russia.
However, it is still a fresh concern for Zidane after earlier in the week Gareth Bale was forced to withdraw from the Wales squad due to a soleus injury.
Real Madrid have not set a timeframe on Bale's recovery but reports in Spain suggests that he is going to be out of action for at least two weeks, missing the upcoming Madrid derby with Getafe and the Champions League visit of Tottenham.
Dani Carvajal, meanwhile, is expected to miss both games amid suggestions that the right-back could be on the sidelines for around two months due to a viral pericardium infection.
The games with Getafe and Tottenham may also come too early for Mateo Kovacic as the midfielder is yet to play a game since suffering a "partial tear of the adductor muscle tendon in his right leg" during the Champions League victory over APOEL Nicosia on 14 August.
Zidane, however, is expected to recover Karim Benzema, Marcelo and Theo Hernandez as the trio completed a full training session on Friday, having returned from their respective injuries earlier in the week.
"The 14 Madridistas currently on duty for their international sides were absent from the session as the rest of the team trained for the third time this week at Real Madrid City. Zidane led a session dominated by ball work which saw Casilla, Marcelo, Theo, Llorente, Lucas Vázquez and Benzema train alongside Under-19s goalkeeper, Moha," the club confirmed.
"Luca worked using the indoor facilities, while Kovacic, Bale and Carvajal continued with their respective recovery programs."