Boston Celtics guard Marcus Smart, who announced Monday that he is clear of COVID-19 after testing positive two weeks ago, confirmed Tuesday night that he plans to donate blood so it can be studied with the hope of finding a treatment for the coronavirus.

Michael Joyner, an anesthesiologist at the Mayo Clinic, told ABC News that at least four NBA players who have recovered from the infection plan to donate blood for the National COVID-19 Convalescent Plasma Project, an experimental treatment that could help high-risk patients recover from the virus.

Smart confirmed through his agent that he is one of the players who opted in. The identities of the three other players were not revealed.

The NBA league office reached out to team physicians Sunday, encouraging players who have recovered from the virus to consider participating in the experimental treatment, according to a copy of the memo obtained by ABC News.

Joyner said Tuesday that he believes the experimental treatment "can be disease-modifying and reduce duration and severity in some patients." The therapy uses the antibodies in blood from recovered patients to potentially curb the virus in sick patients.

Professional athletes could be especially valuable plasma donors, Joyner said.

"These are big men with blood volumes, and as a result [they] have a lot of plasma volume," Joyner said. "Frequently people who are physically trained also have an increase in their plasma volume from what you would expect from them just being regular-sized guys."