"I think it's probably well overdue," James told reporters at Monday's shootaround. "Understanding what he's been going through throughout the season, so obviously health is the most important with everything in life, so I'm not surprised by it at all."
That said, James wasn't ready to pretend the team won't miss its coach while he is taking care of himself.
"It's like losing one of your best players, obviously - the guy who's the captain of our ship, who's been running things the past three years," James added, per ESPN's Rachel Nichols.
A source with knowledge of the situation told Cleveland.com's Joe Vardon that Lue had resisted taking leave at several points throughout the Cavaliers' up-and-down season, including during the team's red-hot stretch from November and December in which they won 18 of 19 games.