James Rodriguez has suffered another calf injury setback as Real Madrid head coach Zinedine Zidane counts the cost of mounting fitness problems for the LaLiga leaders.

Colombia playmaker James has missed Madrid's last four matches in all competitions due to an injury to his left calf and has now damaged the same muscle in his right leg, with local media reports predicting a further two to three weeks on the sidelines.

"James has a problem with his other leg," Zidane said ahead of Wednesday's Copa del Rey trip to Celta Vigo, where Madrid will seek to overturn a 2-1 deficit from the first leg of the quarter-final.

"It is a strain, not a [serious] injury, which is the good part."

Madrid's patchy start to 2017 – Saturday's slender 2-1 win over Malaga was their first victory in four matches – has been accompanied by a growing injury list.

First-leg goalscorer Marcelo and influential midfielder Luka Modric will miss the trip to Vigo after picking up respective hamstring and thigh strains at the weekend and Zidane is already without defensive duo Pepe (calf) and Dani Carvajal (hamstring), with Gareth Bale (ankle) a long-term absentee.

"It's true that we've had quite a few injuries recently, but I just want to say I am responsible for everything," Zidane said, in light of the work of his coaching and medical staff being called into question.

"The people here are doing their best to make sure the players are okay.

"I'd like to have everyone, yes. Am I annoyed that some are injured, yes? But we can't do anything.

"In a season, this happens. Now, it's our turn at the moment, but we're not worried. We just have to keep going with the players that are here."

Zidane insisted he does not regret using key players in back-to-back games during Spain's January slog of alternate LaLiga and Copa del Rey matches and, while he appeared somewhat dejected after the struggles versus Malaga, he called for a more upbeat assessment of a side that set a new Spanish record of 40 games unbeaten before falling to Celta last week.

"It's difficult because you hear all these questions – you'd think that we're last and going against relegation," he said.

"Whatever goes on in the dressing room is normal. If you're worried about injuries or when you lose a game…. I'm not worried. I'm going to keep going and the dressing room [will do] the same.

"I'm excited and we know we've got a big game. It's a great game to play

"When everything is going well things seem easy. Now it's a bit tougher, we're 2-1 down. But it's great to play in these type of games."

Despite exasperation in the Santiago Bernabeu stands on Saturday, Zidane – whose son Enzo and fellow Castilla player Achraf Hakimi were named in a depleted matchday squad, missing rested defender Raphael Varane – insisted he does not fear the wrath of the Madrid fanbase if Celta manage to complete a cup upset.

"I don't think it would be a great failure if we lose, but I'm not thinking about that," he added.

"I'm thinking about the performance we have to put in, but I don't think it would be a great failure."