According to ESPN's Rachel Nichols, Lue's target timetable is around a week.
Lue detailed his health issues in the statement:
"After many conversations with our doctors and Koby [Altman] 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."
The 40-year-old coach missed the second half of Saturday's 114-109 victory over the Chicago Bulls and Monday's 124-117 win over the Milwaukee Bucks. The team has three games to play through Sunday and 12 contests left before the playoffs.
For the Cavaliers, it's never been about the regular season since LeBron James returned in 2014-15. It's always been about the NBA Finals. At 41-29, they hold the third spot in the Eastern Conference in what has been a drama-filled season. While it would be ideal for the coach to get back as soon as possible, Cleveland is in a position where he can focus on his health.
That said, don't be surprised if he is back on the sidelines before the end of the month.
Associate head coach Larry Drew will fill in during Lue's absence.