Preliminary results indicate Atlanta Thrashers goalie Ondrej Pavelec had a type of fainting spell, which caused him to fall and hit his head on the ice during the team's home opener.
In a club statement released Monday, the Thrashers said the episode led to Pavelec's subsequent concussion and loss of consciousness.
Pavelec was released from hospital Sunday and cleared to return home following a battery of testing on his heart and brain. The Thrashers netminder will undergo further tests on his heart as well as blood and genetic testing this week.
The Thrashers said if all goes as expected with the tests, Pavelec will be medically cleared and will be available to resume playing at the conclusion of any symptoms from his concussion.
"I want to thank all the doctors, trainers and emergency personnel who took such good care of me," Pavelec said in a statement.
"I would also like to thank my teammates, all the fans and everyone in the hockey community who have reached out to me and offered their support and well-wishes over the last few days. I hope to be back in action as soon as possible.
Fainting spells are caused by numerous factors, including prolonged standing, standing up very quickly or stress. The puck was in the Washington end of the ice and no one was around when the Atlanta goalie went down, and he had yet to face a shot on goal.
According to the Mayo Clinic, there is a sudden drop in heart rate and blood pressure during a fainting spell, which reduces blood flow to the brain and can result in a brief loss of consciousness. While the condition is usually harmless and requires no treatment, "you can injure yourself," the clinic warns.
That's just what happened to Pavelec, two minutes into Atlanta's first game of the season against Washington on Friday. He fell backward and lay motionless on the ice during a stoppage at the other end of the rink after knocking himself unconscious when he fell back on the ice.
The 23-year-old Pavelec had waved to the bench before his collapse. Trainers from both teams rushed to his aid and, after nearly 10 minutes of treatment, Pavelec left the ice on a stretcher and was taken to a local hospital.
Pavelec, a native of Kladno, Czech Republic, won Atlanta's No. 1 starting job last season.
He played 42 games and had a .906 save percentage with a 3.29 goals-against average in 2009-10. Atlanta selected him 41st overall in the 2005 draft.