Marc Wachs, 21, was "seriously injured" and had to undergo an emergency operation following the incident at a corner shop in the town of Wiesbaden although his condition is not life-threatening, the club said.
Wiesbaden police, without naming the victims, said a 59-year-old woman was killed in an incident on Tuesday at a shop where she worked and that her husband and 21-year-old nephew were hurt.
Police said they were looking for a male suspect. German media said the incident was a robbery.
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"We are shocked, bewildered and deeply affected. The entire Dynamo family is behind Marc and his family," Dresden's sporting director Ralf Minge said in a club statement.
"We will be wherever our help and support is needed. Marc, his family, and the process of recovery, both physically and mentally, now come above everything else."
Wachs, a left back, was raised at Mainz 05 and played for their reserve team in the last two seasons.
He joined Dresden on a free transfer this year and has been on the bench for several games, but is yet to make his professional debut.
(Writing by Brian Homewood in Berne, editing by Ed Osmond)
