"She needs to get her immune system replaced. How that process works is by getting a blood transfusion with these stem cells that hopefully come from a donor in Kamloops, because she doesn't have a match right now," he told Daybreak Kamloops' Shelley Joyce.
It's not just Reid's sister who could benefit from a donation.
"Everyone is touched by cancer and hopefully by doing this we can help save a lot of lives across Canada," he said.
Reid contacted Canadian Blood Services and set up a donation clinic.
"You swab your mouth in four different places with four different swabs … and it's a super easy process."
If the donor is a match, blood is drawn and the stem cells are separated.
Anyone between the ages of 17 and 35 in good health can sign up to become a donor.
The clinic will be held on Thursday, March 12 between 10 a.m. and 2 p.m. PT in the Wolf Den at the Tournament Capital Centre.
To hear the full interview with Alex Reid, click the audio labelled: Stem-cell donor sought by TRU baseball player for his sister.