Cleveland Cavaliers head coach Tyronn Lue will step away from the team due to an illness, the team announced Monday. Lue missed parts of all of the team’s last three games with an unknown illness that has affected him all year.

Lue only plans to be absent one week for now, per TNT’s David Aldridge.

“I have had chest pains and other troubling symptoms, compounded by a loss of sleep, throughout the year,” Lue said in a statement. “Despite a battery of tests, there have been no conclusions as to what the exact issue is.”

In the interim, associate head coach Larry Drew will coach the Cavaliers. Drew has two head coaching stints on his resume — with the Atlanta Hawks from 2010 to 2013, and for the Milwaukee Bucks during the 2013-14 season.

“My goal is to come out of it a stronger and healthier version of myself so I can continue to lead this team to the championship we are all working towards,” Lue said.

Lue’s illness has been severe enough that LeBron James recently said Lue leaving the bench during a game has stopped surprising him or the team, since this illness has lasted so long.

“We know how difficult these circumstances are for Coach Lue and we support him totally in this focused approach to addressing his health issues,” Cavaliers general manager Koby Altman said in a statement.

Here is Lue’s full statement, released through the team:

“After many conversations with our doctors and Koby and much thought given to what is best for the team and my health, I need to step back from coaching for the time being and focus on trying to establish a stronger and healthier foundation from which to coach for the rest of the season.

I have had chest pains and other troubling symptoms, compounded by a loss of sleep, throughout the year. Despite a battery of tests, there have been no conclusions as to what the exact issue is.

While I have tried to work through it, the last thing I want is for it to affect the team. I am going to use this time to focus on a prescribed routine and medication, which has previously been difficult to start in the midst of a season. My goal is to come out of it a stronger and healthier version of myself so I can continue to lead this team to the Championship we are all working towards.

I greatly appreciate Dan Gilbert, Koby Altman, our medical team and the organization’s support throughout.”