Worrying signs for Real Madrid emerged when Karim Benzema left Tuesday's UEFA Champions League Group Stage encounter against Celtic with a knee injury. The Frenchman was unable to endure the pain any longer.

After 30 minutes, he went directly to the locker room, which was not good news for Los Blancos. The Frenchman was replaced by Eden Hazard shortly after.

Real Madrid coach Carlo Ancelotti, though, was unconcerned after the game. "We don’t think Benzema has a big problem. It’s muscular. We have to wait for the tests tomorrow. Then we will know what Benzema has.”

How serious is Benzema's injury and how long he will be out?

Today, Real Madrid released a statement saying, "he has been diagnosed with an injury to the semitendinosus muscle and an overload on the quadriceps, both in the right leg." Simply put, the Frenchman has hurt his hamstring.

Initial reports suggested that the star player would be out for an extended period. However, Benzema is expected to be unavailable for the next three weeks, as per Spanish publications Marca and AS. The 34-year-old is believed to miss the international break with France and should be available for the October match against Osasuna.

Carlo Ancelotti's side will surely benefit greatly from the international break. There was an initial estimate that Benzema would be out for six to seven games, however, that estimate has been reduced to only three games thanks to it. Thus, he will not be able to play against Real Mallorca on September 11, the Madrid derby against close rivals Atletico Madrid on September 18, and will miss the UEFA Champions League clash with Leipzig three days later.

The good news about Karim Benzema stems from his extensive career history. As soon as he could, he signaled for a change, unwilling to take any chances that may have made the damage worse, the Spanish media suggest.