Hammel could start Game 4 of the best-of-five series against the NL Central champion St. Louis Cardinals but also will be available out of the bullpen.
Berry was on the NL wild-card roster.
Both the Cubs and Cardinals are carrying 11 pitchers.
Cubs manager Joe Maddon had far few pressing decisions to make than Cardinals manager Mike Matheny. The Cardinals left first baseman Matt Adams; relievers Randy Choate and Steve Cishek; and utilityman Pete Kozma off their roster.