Real Madrid have been left counting the cost of Saturday's 2-1 home win over Malaga after Luka Modric and Marcelo suffered injuries.
Real announced on Monday that Modric, who was replaced 12 minutes from time, strained his right abductor muscle although they did not outline how long he will be sidelined for.
Brazilian left-back Marcelo lasted 25 minutes of the game at the Bernabeu before coming off with what has been diagnosed as a "grade 2" hamstring injury.
Marca reports that the two players could be out action for up to four weeks.
Real were already without injured trio Pepe, Dani Carvajal and Gareth Bale.
"I'm a bit fed up with the injuries because we've got a lot of games ahead and I'm a bit downbeat," Real coach Zinedine Zidane said to the club's official website. "We've got an important game on Wednesday and we'll have to see what happens."
Real travel to Vigo to face Celta on Wednesday needing to overturn a 2-1 first-leg deficit to reach the Copa del Rey semifinals.
To complicate matters for Zidane, Real forward Cristiano Ronaldo is doubtful with a minor knock sustained against Malaga.
The injuries to Modric and Marcelo could rule them out for the first leg of Real's Champions League round-of-16 tie with Napoli on Feb. 15 at the Bernabeu. Real are one point clear of Sevilla at the top of La Liga but have a game in hand.
Sunday's win allowed Real to bounce back from two consecutive defeats -- a 2-1 league loss at Sevilla, which ended their record-breaking 40-game unbeaten run in all competitions, followed by a 2-1 reverse at home to Celta in the Copa.