The 36-year-old suffered cuts to his back in the incident which occurred as members of the Wolfsburg squad celebrated the end of the Bundesliga season.

The club confirmed Lenz lost a lot of blood in the incident, in which three other people also received injuries, but they were unable to disclose any further details pending a police investigation.

No other members of the Wolfsburg squad were among the injured.

"We deeply regret the incident," Wolfsburg's managing director Dieter Hoeness told the club's website.

"We don't yet have precise information about what happened and we will have to await the police investigation and obviously co-operate with them.

"As soon as we heard that Andre Lenz was seriously injured, we were deeply shocked.

"Andre is a very respected player in our team and we are glad that, given the circumstances, he and the other three injured people are fine. It could have been worse."