CHICAGO - The Chicago Blackhawks say defenceman Trevor van Riemsdyk had left knee surgery on Thursday, sidelining the rookie for three to four months.

He broke his left kneecap when he took a puck off his leg during Sunday's 6-2 victory over Dallas.

The 23-year-old van Riemsdyk has one assist in 18 games. He was placed on the long-term injury list on Monday. Chicago begins a six-game road trip on Thursday at Calgary.