The drive will take place Wednesday from 11 a.m. to 7 p.m. CT at the Toyota Center in Houston, prior to the Rockets' regular-season finale against the Sacramento Kings.
Hosting the blood drive in conjunction with Gulf Coast Regional Blood Center is the Gulf Coast Marrow Donor program. Everyone who donates or attempts to donate will receive a commemorative T-shirt featuring an illustration of Howard and Sager with the hashtag #SagerStrong.
"I know a lot of people deal with a lot of different types of cancers and leukemia," Howard said. "Craig is a close friend of mine, my family. He's part of the NBA family. You hate to see anybody who is a part of you go through anything. I just want to do whatever I can to help."
In April 2014, Sager was diagnosed with leukemia, which went into remission after treatment. Sager returned to TNT last March, but the cancer has since returned. Sager is undergoing cancer treatments in Houston.
"I've lost family members, [and] one of my closest friends is battling breast cancer right now," Howard said. "Just a lot of different things going on that I just try to find ways to help."