Jim Boylan, who coached in Skiles' absence, said the coach was doing well.
"He's fine," Boylan said. "He'll be joining us in Portland. He has a little arrhythmia."
Skiles spoke to the media shortly before the game and showed no signs of illness.
A team spokesman said Skiles was hospitalized for precautionary purposes.
Skiles, 45, is in his second year as Milwaukee's coach. Last season, he guided the team to a 34-48 record. This season, the Bucks were 15-19 coming into Monday night's game.
"When something like that happens, it's bigger than basketball," Milwaukee's Hakim Warrick said. "You just have to hope for the best."
Skiles coached the Suns from 1999-2002 and the Chicago Bulls from 2003-2008.
He played 10 seasons in the league with Milwaukee, Indiana, Orlando, Washington and Philadelphia.