Fellow forward Wayne Primeau will miss two to four weeks with a knee injury, the team announced Sunday.
Grabovski suffered the injury during the first period of Saturday's 3-1 loss at Calgary. He's currently tied for fifth in team scoring with 25 points (7 goals, 18 assists) in 42 games.
Primeau was injured during the third period. He has two goals and three assists in 35 games.