The 31-year-old died while playing with Latvian club Riga 2000 in Belarus on Wednesday night.
Zholtok, an 11-year NHL veteran, was popular in his homeland for his tireless dedication to the national team. He regularly suited up for Latvia at the IIHF world championship after his NHL seasons were over.
"I was really honoured to have him on the team," said an emotional Riga 2000 president Viesturs Kozioles. "He was a patriot for his country and for hockey who never took a shift off and always devoted time to trying to make our young players better."
Sergei Zholtok, shown here in an old photo playing with the Ottawa Senators, passed away in Latvia on Wednesday night. (CP File Photo)
Zholtok, along with goaltender Arturs Irbe and defencemen Sandis Ozolinsh and Karlis Skastins, was one of a small group of Latvians to have a lengthy career in the NHL.
"He was one of the greatest all time players in Latvian hockey history," said Guntis Keisels, a sports reporter with the country's leading newspaper Diena. "Ten years in the NHL is quite an achievement. He was the best goal scorer, the best forward, Latvia ever produced."
News also shocked Zholtok's friends in the NHL.
"This isn't something you expect," Islanders centre Alexei Yashin, who played with Zholtok from 1996 to '98 with the Senators, told the Ottawa Sun. "We were close friends and this is hard.
"We used to work out together in the summer from time to time and we also kept in touch quite a bit. We played together on the national junior team (in 1992) in Russia and he was a guy I really respected. I'm going to miss him."
Zholtok excused himself from Wednesday night's game against Dynamo Minsk about five minutes before it ended. He went back to the dressing room, where he collapsed and died.
Zholtok was diagnosed with an irregular heartbeat last year.
He missed games a couple of times last year with mysterious health ailments that included dizziness and fatigue. In January 2003, he left a game and was hospitalized overnight for observation.
Zholtok was a key forward for the Wild during their unexpected playoff run two years ago. He was traded to Nashville late last season.
Drafted 55th overall by Boston in the 1992 NHL Entry Draft, Zholtok scored 111 goals and 258 points in 588 career NHL games with the Bruins, Ottawa, Montreal, Edmonton, Minnesota and Nashville.