Tyronn Lue was unable to coach the Cleveland Cavaliers for the entirety of Saturday's 114-109 victory over the Chicago Bulls, and LeBron James says the players are concerned.
Lue stayed in the locker room for the second half at United Center, with assistant coach Larry Drew taking over his duties for the remainder of the match.
It is the third time this season Lue has been unable to see out a full match, and James, whose triple-double (33 points, 13 rebounds, 12 assists) proved key to the Cavs' latest win, suggested his absence has an impact on court.
Asked if the coach's health has affected the team this season, James said: "He's the captain of the ship, so absolutely.
"We worry about his health, obviously. That's way more important than this game of basketball.
"We know he's been doing everything he needs to do to stay healthy, take even more measures to get himself right. Everything that's been going on with our year, it's just another one.
"It doesn't catch us off-guard because he's been dealing with it for so long now, but any time he doesn't come back to the bench, it's just an alarm going off."
Cavs coach Tyronn Lue is not on the bench to start the second half. He missed one game earlier in the season because of an illness and had to leave another game early because he was not feeling well. No update from the Cavs on his status as of yet. Larry Drew just ran the huddle— Dave McMenamin (@mcten) March 18, 2018
Lue did not speak to the media after the match and Drew was unable to provide a detailed update on the head coach's condition.
"I'm not sure exactly what it is, I just know that before coming out in the second half, he wasn't feeling well," said Drew.
"I don't know if it's impacting the team. I think, particularly at this stage of the season - this is the last day of a 13-day road trip - certainly some elements are going to come up.
"Sometimes these things, they come up and are unavoidable, and you just have to deal with it, but we know as a staff, if he's not feeling up to par, we have to step up, and that's just what we did."