An item of footwear having an interchangeable sole system, midsoles for such an item of footwear, and related methods for making such midsoles, including a receptacle incorporated in the midsole wherein a portion of the receptacle is configured to complement an engageable element of a sole unit so that a bidirectional stop is provided that helps secure the sole unit to the midsole, and wherein a material property of the receptacle differs from a material property of the midsole so that the midsole provides cushioning to the item of footwear, and the receptacle allows for engagement and disengagement of the engageable element of the sole unit to the midsole without the need for an outsole frame.