Real Madrid have confirmed that right-back Dani Carvajal has sustained a calf injury, which is expected to rule him out for the remainder of the calendar year.
The Spain international has been bedevilled by numerous fitness problems over the past couple of seasons, previously missing clashes with Atletico Madrid and Union Berlin in September with a muscular injury.
Carvajal has largely managed to banish his injury demons this term, though, and he wore the captain's armband for Saturday's 2-0 win over Granada in La Liga.
"Carvajal, I think it's an overload. We're going to evaluate it tomorrow, but it doesn't seem like anything very serious," Ancelotti told reporters at his post-match press conference.
Tests have since been carried out on the Spaniard, and Ancelotti's optimism was unfortunately unfounded, as Carvajal is now expected to miss the remainder of 2023.
"After the tests carried out on our player Dani Carvajal by the Real Madrid Medical Services, he has been diagnosed with an injury to the soleus muscle in his left leg. Evolution pending," Real said in a statement.
Should Carvajal indeed miss the rest of the calendar year, the experienced defender will sit out meetings with Real Betis, Villarreal and Alaves in La Liga, as well as Los Blancos' final Champions League group-stage showdown with Union Berlin.
Carvajal's participation in Real's first clash of 2024 against Mallorca on January 3 is also in doubt, but the former Bayer Leverkusen man is supposedly optimistic of being back in time for the Supercopa de Espana.
Ancelotti's side will meet local rivals Atletico in their semi-final in Riyadh on January 10, and victory would set up a showdown with Barcelona or Osasuna in the final four days later.
With Carvajal set for a few weeks on the sidelines, Vazquez will be expected to fill in at right-back for the remainder of the calendar year in place of his compatriot, whose experience will be sorely missed by Real over the festive period.
The Blancos youth product - who spent one year at Leverkusen from 2012 to 2013 - boasts nine goals and 61 assists in 392 matches for Real Madrid, with whom he has won 23 major honours.
Meanwhile, Aurelien Tchouameni (foot) and Luka Modric (hamstring) both sat out the win over Granada, while Turkish teenager Arda Guler is yet to make his Real debut owing to setbacks in his recovery from a thigh injury.
Goals from Rodrygo and Brahim Diaz saw Ancelotti's side ease to a two-goal win over Granada at the weekend, keeping them above Girona at the top of the table on goal difference ahead of Saturday's trip to Betis.