Real Madrid forward Gareth Bale is reportedly set for three weeks on the sidelines after the club confirmed he sustained a calf injury in the Clasico defeat to Barcelona.

Bale missed Madrid's recent games with Sporting Gijon and Bayern Munich due to a muscular problem, but somewhat surprisingly featured from the start at the Santiago Bernabeu on Sunday.

However, coach Zinedine Zidane was forced to replace the winger shortly before half-time with an apparent recurrence of a calf problem.

The Wales international now appears to be a doubt for both legs of Madrid's Champions League semi-final tie with city rivals Atletico Madrid.

Zidane, though, insisted Bale was fully fit to play in the 3-2 loss to Barca.

The Frenchman told a media conference ahead of Wednesday's clash with Deportivo La Coruna: "Bale was 100 per cent. He told me he was at 100 per cent, that the two training sessions before the game were perfect. We cannot avoid this happening.

"Injuries happen, it is part of a player’s life, nobody can do anything about that."

"I hope he is back before the end of the season. It's grade two [the severity of the injury], yes. But the doctors tell me it's a small thing. I trust the staff here."

Madrid's loss to Barca saw them drop to second in the table behind their arch-rivals due to an inferior head-to-head record, though Zidane's men do have a game in hand.