Modric played a little over an hour in Real's 4-2 defeat by Girona over the weekend before he was substituted.

Real will be looking to win the Copa del Rey for the 20th time.

"He had an injury in the match against Girona and is out of action," Ancelotti told reporters ahead of Saturday's LaLiga game against Almeria.

"It's pending evolution and we don't know if he will be fit for the Copa match. We are hurt and we hope he can recover soon to play in the important matches".

Real host Manchester City in the first leg of their Champions League semi-final on May 9.

They currently sit second in LaLiga, 11 points behind leaders Barcelona after 31 games and two points ahead of Atletico Madrid. Ancelotti's side also face fourth-placed Real Sociedad in the league on Tuesday.