Craig Sager, the veteran sideline reporter famous for his outrageous attire, is battling leukemia, the New York Daily News reports.

The news was shared via Twitter by his son Craig Sager Jr.

"My Dad's 3-4-week acute leukemia treatment starts tmrw," Sager Jr. tweeted on Thursday night. "Be thinking of him & let's get him back on the sidelines soon."

Sager, a graduate of Northwestern University, has been a fixture on TNT as a key piece of the network's NBA coverage. He's been part of the "NBA on TNT" for 17 seasons.