Kemba Walker Ruled out for Celtics vs. Bulls with Non-COVID-19 Illness

Boston Celtics star Kemba Walker will miss Monday's game against the Chicago Bulls with an undisclosed illness.

Head coach Brad Stevens told reporters Walker's illness isn't COVID-19-related.

The four-time All-Star didn't make his 2020-21 debut until the Celtics' 105-75 loss to the New York Knicks on Jan. 17.

Walker had undergone a stem cell procedure to address a nagging knee problem and spoke positively about its effects after returning to the court:

The 30-year-old's absence highlighted how top-heavy the Celtics had become after losing Gordon Hayward to the Charlotte Hornets in a sign-and-trade. 

Compounding matters, Stevens was without Jayson Tatum, too, while the 2020 All-Star was quarantined under the NBA's COVID-19 health and safety protocols.

In general, Boston's depth falls off quite a bit once you get beyond Walker, Tatum, Jaylen Brown and Marcus Smart. Take one or more of those players away and the Celtics' ceiling is significantly lower.

Walker is signed for $36 million in 2021-22 and has a $37.6 million player option for 2022-23, so staying off the injury report is crucial for Boston to capitalize on its championship window over the next few seasons.