Ballack aggravates old injury in knee
The 34-year-old Germany captain, who was left on the bench in Saturday's 3-0 win at Eintracht Frankfurt, missed training on Sunday but should return by the middle of next week.
"Whether he will be able to be back on Tuesday when the team does their first training sessions of the week depends on the process of the treatment," the club said in a statement.
He had returned to action only in late January after being out since September with a shinbone injury.
Ballack, who also missed the World Cup last year through injury and is battling to win back a place in the national side, was surprisingly left on the bench on Saturday after spending 40 minutes warming up in the second half.