My tendon on pinky finger was severed. Will I be able to play volleyball again?

Maybe. Which tendon, palm side or nail side of the finger. Was it repaired? Can you move the last joint of the finger? Can you move either joint of the finger?
Possibly. A lot will depend on which tendon, how well it was repaired, and how therapy goes post-operatively. Injuries on the dorsal side of the finger tend not to be as severe as those on the volar or palm side and there are zones on the palm side that are far worse prognostically than others. A lot will also depend on a given individuals ability to adapt to less than perfect function and level of play.