The injury isn't as bad as the Eagles initially feared, per Rapoport, and the linebacker will meet with Dr. James Andrews to get a second opinion. That will determine if Alonso's season is over or if he can return to the field at some point this year.
The injury is to the same knee that was surgically repaired following an ACL tear in the summer of 2014. Alonso also tore his right ACL in college and underwent hip surgery earlier in 2014.
This is a big loss for Philadelphia and a crushing blow to Alonso's future prospects.