Spurs coach Gregg Popovich misses game against Timberwolves because of undisclosed illness

Popovich has been with the Spurs for over two decades

Gregg Popovich, the head coach of the San Antonio Spurs, missed the team's game against the Minnesota Timberwolves on Wednesday night due to an undisclosed illness.

Assistant coach Becky Hammon took over as acting head coach in Popovich's absence.

The Spurs lost to the Timberwolves 108-106.

Popovich is considered one of the greatest coaches in NBA history

Popovich has been the head coach of the Spurs since 1996.

He has led the Spurs to five NBA championships.

Popovich is also the winningest coach in Spurs franchise history.

The Spurs are currently in the midst of a rebuilding season

The Spurs are currently 14-21 this season.

They are in 13th place in the Western Conference.

The Spurs are in the midst of a rebuilding season after trading away Dejounte Murray and Derrick White in the offseason.

Hammon is the first woman to serve as acting head coach in the NBA

Hammon became the first woman to serve as acting head coach in the NBA when she took over for Popovich on Wednesday night.

She has been an assistant coach with the Spurs since 2014.

Hammon was a six-time All-Star during her playing career.