A rotor assembly (302) that has a support tube (608) having a first diameter, at least one tooth (324) coupled to the support tube (608), wherein the tooth (324) rotates with the support tube (608) to direct crop toward a chamber (128, 218), and an undershot auger (304, 306) having an auger flight extending radially away from an auger core (314, 316), the auger flight (308, 310) configured to cause the crop to flow towards a bale chamber region of the rotor assembly (302) when rotation of the rotor assembly (302) causes the crop to flow under the rotor assembly (302). Wherein, the auger core (314, 316) has a second diameter that is greater than the first diameter.
