The New Orleans just got some bad news about one of their best defenders.

Tony Allen is expected to be out 3-4 weeks with a non-displaced left proximal fibula fracture, per David Aldridge of TNT.

Allen suffered the injury during the Pelicans' 131-124 win over the Philadelphia 76ers on Sunday. It was late in the first quarter, and Allen had been in the game for only one minute before suffering the injury as he was trying to fight through a screen.

The news of his injury is a big blow to the Pelicans, who had just seen Rajon Rondo return to their lineup after missing some time on the injured list himself. Now the Pelicans have to wait until yet another of their key players heals.

The Pelicans have had trouble with injuries over the past few years, and this season has been no different thus far. Allen is considered one of the best perimeter defenders in the entire league, which is why New Orleans went after him in the first place.

With Allen missing about a month of time, the Pelicans defense will surely suffer, and it could cost them some games. They need him to recover quickly if they want to make the playoffs in the Western Conference.