The 30-year-old picked up the ligament problem on international duty with the Netherlands during a goalless draw with Colombia.
Medical staff at Hamburg initially predicted Van der Vaart would be "missing for some time", but the club have confirmed the attacker will make his comeback sooner than expected.
Hamburg have endured mixed fortunes in the Bundesliga in his absence, winning one, drawing one and losing another.
Van der Vaart has scored six goals in 12 German top-flight appearances this season.
Hamburg next face a daunting away tie at leaders Bayern Munich on Saturday - a fixture they lost 9-2 last season - though it is not yet clear whether Van der Vaart will be in the starting line-up.
