Kassian collided with Gagner along the boards in the second period of the Oilers' 5-2 home exhibition win over Vancouver on Saturday. Kassian's stick struck Gagner's face, knocking out several of the Edmonton forward's teeth.
Gagner will miss the start of the regular season with the injury. The team said he is out indefinitely.
Kassian received a double-minor for high-sticking on the play.
Weise's incident occurred early in the first period. He was assessed a minor penalty on the play for illegal check to the head.
Hall remained in the game and showed no apparent injury.