The 24-year-old is set to be out for 12 weeks and will miss England's tour of Argentina in June.
"The issue needs addressing immediately," Harlequins director of rugby John Kingston said.
Clifford lasted just five minutes of Quins' defeat by Saracens at Wembley on Saturday because of a head injury.
Harlequins and England back row Jack Clifford has been ruled out of the rest of the season as he requires surgery on a persistent shoulder injury.