Denver Nuggets Ahead, Michael Porter Jr.. ESPN Monday.
Bartelstein added that Porter is expected to make a full recovery, and the timeline for his return will come after surgery.
Porter, who signed a five-year maximum, $172 million contract in September, had been looking at a non-surgical option since injuring his back on November 6, but differing opinions led to an operation.
The 23-year-old Porter underwent back surgery before the 2018 NBA Draft and spent his first season recovering, becoming one of the top young strikers in the league.
He averaged 19 points last season and formed a partnership with the MVP. Nikola Jokic and the base Jamal Murray Which represents one of the best young cores in the league.
Murray is recovering from an ACL tear and Jokic is expected to be back soon from a wrist injury.
Denver (9-10) lost six straight games and started a seven-game road trip in Miami on Monday.