The 25-year-old midfielder arrived from Real Madridas a makeweight in the Michael Owen deal and his first day at his new club will not be a cherished memory following a knee ligament injury in training.
Benitez said: "Antonio is very unfortunate and it is just a case of bad luck. He was training and just chased a long pass when the knee went.
"We are lucky because we thought it was a lot worse than it has turned out and Antonio should be training again in about three to four weeks."
