By Lucia Hoffman

KEY BISCAYNE, Florida – Rafael Nadal withdrew from his scheduled semifinal contest against Andy Murray with a left knee injury at the Sony Ericsson Open.

There had been some speculations that Nadal was in pain during his quarter final match against Jo-Wilfried Tsonga. He didn’t practice yesterday and was not in the practice schedule for Friday.

Rafa Nadal was very apologetic.  Nadal doesn’t know the severity of his injury yet and will see a doctor soon. “I have problems on the left knee, Nadal said. “I cannot  I have to go to doctor, but looks like is nothing really, really different that happen a few times in the past.

“Just go to the doctor hopefully tomorrow, and hopefully in a few days, with a few days off and with the right treatment, I will be in the right conditions to start to practice on the clay.”

Nadal repeated himself many times apologizing to fans, to the tournament , to television, “to everybody”. “I can not play today… I want to play here with the right condition… This tournament is very important to me. I feel sad.”

Lucia Hoffman is in Miami covering the Sony Ericsson Open for Tennis Panorama.