Novak Djokovic reacts after missing a point during his match against Roger Federer in Saturday's semifinal at the Monte Carlo Masters in Monaco. Federer won 7-5, 6-2. Patrice Masante / Reuters

Novak Djokovic said he has no idea when he will play again after a right wrist injury contributed to his 7-5, 6-2 Monte Carlo Masters semifinal loss to Roger Federer on Saturday.

World No 2 and defending champion Djokovic, who played with a brace on his wrist, revealed he felt pain in his wrist all week. But with the French Open just five weeks away, and his next scheduled event the Madrid Masters in two weeks, timing is everything for the Serb who won the 2013 Monte Carlo title against Rafael Nadal.

"I'll just rest now. I cannot play tennis for some time - how long, I don't know," said Djokovic. "It's really not in my hands anymore. I'm going to rest and see when it can heal 100 percent, then I will be back on the court.

"The good thing is I don't need to have a surgery; I don't have any rupture or anthing like that. I'm going to go see the doctors tomorrow and have another MRI, see if anything changed in the seven days since I had the last one."

Djokovic, whose loss ended a 13-match win streak and a run of 23 in a row at the Masters level, said he had to play through the pain barrier all week in his aborted title defense.

"The pain was there every single day from 10 days ago; at some stages it was very painful. Between my first and second match I had a day off so I didn't practice at all and I healed a little bit.

"Yesterday's conditions (a quarterfinal win over Guillermo Garcia-Lopez) did not help the state of my arm. It was a long match, with long rallies.

"I really don't know the diagnosis, to be honest. But trust me, it's complicated."

While it is too early to panic regarding the French Open - the only Grand Slam title missing from his collection - Djokovic is still puzzled about how he was injured.

"I had two weeks between Miami and Monte Carlo (in March). It's not like I was tired or I had some long trips or something like that. It just happened during the practice week, sometimes it just happens. Sometimes it's not predictable."

Federer said he knew Djokovic was not at his best.

"I saw that Novak was struggling at one point," said the Swiss,.

"For me it was more just making sure that from my side I was playing a good, solid, tough match with some good defensive play ... but mostly I was trying to stay on the offensive as much as I could."