A threshold assembly for use with an entryway disposed within an aperture of a structure, which has an exterior and an interior and includes a door panel moveable between open and closed positions, includes a sill and a rail. A rail is rotatably supported above the upper sill surface between an initial position when the door panel is in the open position, and a second position different from the initial position when the door panel is in the closed position. A biasing member is disposed between the upper sill surface of the sill to bias the rail from the second position toward the initial position. A protrusion extends from the sill towards the rail, with the protrusion configured to rotatably support the rail and configured to prevent the biasing member from rotating the rail beyond the initial position.