The Detroit Red Wings will be without top defenseman Mike Green for the start of the regular season as he deals with a virus that has led to ongoing fatigue.

Red Wings general manager Ken Holland told the Detroit Free Press that Green "hasn't had a lot of energy," which led to him getting blood work done and then a follow-up appointment with a doctor.

Henrik Zetterberg will retire from the NHL due to a back injury.

Zetterberg had been holding out hope that he would be able to play again. Last month, he described a deteriorating condition that included nerve pain in his legs and disk-related issues.

Zetterberg has three years remaining on his contract, with an annual cap hit of $6.083 million.