Murray out of Madrid with back injury

MADRID (AP) -- Fourth-ranked Andy Murray has pulled out of the Madrid Open with a back injury.

Murray says it is "a big disappointment" to miss the Masters series event, but that he is following his doctor's advice. He reached the quarterfinals here the last two years.

Murray last played on April 27, when he lost to Milos Raonic 6-4, 7-6 (3) in the quarterfinal of the Barcelona Open.

The player from Scotland will miss out on the opportunity to play on the new blue clay at the Madrid Open. It's replacing the traditional red-clay surface at the event, but players have complained it's slippery and provides a different bounce.