Pittsburgh Penguins captain Sidney Crosby has been diagnosed with a concussion, the team announced Monday.
Crosby sat out a preseason game against the Columbus Blue Jackets on Saturday because he was not feeling well and missed practice Monday to have concussion testing.
"He came to the rink on Saturday not feeling well and we went from there," Sullivan said. "We always have our players' best interest (in mind). ... This one will be no different."
Crosby, a two-time Hart Trophy winner and runner-up last season, won the Stanley Cup for the second time with the Penguins and was awarded the Conn Smythe Trophy as the MVP in the Stanley Cup playoffs.
Crosby has a history with concussions after a collision in the 2011 Winter Classic set off a long recovery that shortened two seasons for him.
The 29-year-old Crosby also was named MVP of the World Cup of Hockey 2016 after leading all scorers with 10 points (three goals, seven assists) to help Team Canada win the tournament last month.
The Penguins will raise their Stanley Cup banner before opening the regular season against the Washington Capitals at PPG Paints Arena on Thursday night.