A port and closure assembly for a container is provided. The port and closure assembly includes a port having a tubular portion that extends from a base and terminates at an end including an opening. The tubular portion is divided into an upper and lower section by a pierceable membrane. The upper section including an end that terminates at the opening and including a resealing injection site. A closure member for removably surrounding at least a portion of the end of the port including the opening is provided. The closure includes a sleeve that circumscribes at least a portion of an outer surface of the upper section of the tubular portion. The sleeve is so constructed and arranged as to cause portions of the upper section to contact the resealing member during a sterilization step that softens the portions and further causes the portions of the upper section to retain the resealing injection site within the tubular portion after the portions have hardened.