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."
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."
|Brewers allow Cardinals to inch closer with loss to Reds|
|Orioles become first pro team to wear braille jerseys|
|Cubs reliever Morrow won´t return this season|
|Tebow expected to be back in Mets organisation next season|
|Seahawks DE Clark on Bears QB Trubisky: He´s nothing special|
|Carroll says Wilson has been ´over-trying a little bit´|
|Judge returns to Yankees´ starting lineup|
|Waiters injury update: Heat guard unlikely to be ready for start of season|
|Brown absent from Steelers facility on Monday due to ´personal matter´|
|Tomlin confirms Steelers WR Brown was absent from facility on Monday|
|Braves fall to Cardinals, still move closer to clinching NL East|
|Mack leads Bears past Seahawks|
|Lithuania qualify for FIBA World Cup after double-overtime win|
|Yelich makes history with another cycle|
|Brady discusses Patriots´ trade for Gordon|
|Bills coach McDermott hasn´t spoken to Davis, says he ´didn´t feel a need´|
|Gruden doesn´t regret decision to trade Mack|
|Patriots sign Josh Gordon from Browns|
|Carson Wentz injury update: Eagles QB cleared to play Week 3 vs Colts|
|WATCH: Broncos punter Marquette King trolls Jon Gruden in Twitter video|
|Matthews: NFL ´out of control´ protecting quarterbacks|
|Diamondbacks´ playoff hopes fade on rough road trip|
|Mahomes, Fitzpatrick put up impressive numbers in big NFL wins|
|Dwyane Wade returning to Heat for ´one last dance´|
|Greece, Germany qualify for FIBA Basketball World Cup|
|Garrett on Browns parting ways with Gordon: Nobody was expecting that|
|Browns´ Gonzalez on missed kicks: I just let everybody down|
|´He told us he was done´ – Bills coach McDermott says Davis retired at half-time|
|Vikings tie Packers in OT after kicker misses three field goals|
|Chiefs QB Mahomes sets NFL touchdown record|
|Falcons´ Kazee ejected for hit on Panthers QB Newton|
|Gordon says farewell to Cleveland: ´It´s been a hell of a journey´|
|Dodgers reclaim first in NL West, Cubs and Astros extend leads|
|Browns release WR Josh Gordon|
|Rodgers practices but Packers QB still questionable|
|Seahawks star Baldwin to miss Bears showdown|
|Braves make unwanted history against Nationals|
|Indians first team to clinch MLB division with 15-0 win over Tigers|
|Nigeria and Tunisia seal FIBA Basketball World Cup spots|
|Browns´ Josh Gordon out of Saints game with hamstring injury|
|McCutchen reaches base five times to lead Yankees past Blue Jays|
|Ukraine upset Spain, USA cruise to win|
|Yankees activate Judge from disabled list|
|Falcons to be without Freeman for Panthers game|
|Rodgers injury update: Packers QB ´getting better´, still ´day-to-day´|
|Wade still unsure if he will play in 2018-19: ‘I wish I had an answer´|
|Peterson discusses eventual retirement|
|Baez´s bunting skills send Cubs past Nationals|
|Green, Dalton help Bengals past Ravens|
|Red Sox´s Cora objects to Trump´s tweets on Puerto Rico: This is about human beings|
|Cubs lose closer Strop to hamstring injury|
|France stunned by Bulgaria in qualifying|
|Ravens linebacker Mosley suffers knee injury|
|Ramsey on Gronkowski: I don´t fear no man, period|
|Packers WR Adams felt ´good´ in limited return to practice|
|Browns´ Mayfield praises Brees to continue the love|
|Roethlisberger misses practice as Dobbs leads offense|
|Chargers defensive end Bosa out for week two, possibly longer|
|Senators captain Karlsson dealt to Sharks|
|Celtics´ Hayward says ankle is ´basically 100 per cent´|
|This Week in U.S. Sports: This is the story of a hurricane|
|Rodgers injury update: Vikings expect Packers QB who ‘walks on water’ to play|
|Brewers cut Cubs´ advantage, Rockies keep lead in NL West|
|Blue Jays rookie Tellez doubles again, first to accomplish feat since 1913|
|Predators forward Watson suspended for 27 games|
|Packers taking Aaron Rodgers´ injury ´day by day´|
|Price doesn´t plan to opt out of Red Sox contract|
|Beasley and Cowboys not hitting panic button|
|Titans QB Mariota on track to face Texans|
|Drew Brees: Baker Mayfield can be a lot better than me|