McCollum has collapsed lung, will be further evaluated
As a result, the eight-year pro didn't travel with the club for its matchup against the Golden State Warriors on Wednesday.
McCollum suffered the injury to his ribs on Dec. 4 against the Boston Celtics.
The team initially listed him as probable for Monday's contest against the Los Angeles Clippers before eventually ruling him out.
McCollum is averaging just 20.6 points per game this season, his lowest output since the 2014-15 campaign.
- Report: Nets agree to find new team for Millsap
- Nets fined $25K, assistant Vanterpool docked $10K for interference vs. Wizards
- Report: Vogel had approval from Lakers to bench Westbrook
- Jaren Jackson's defensive leap is powering the Grizzlies' rise
- LeBron surpasses Curry in All-Star fan vote one week before starters announced