Introducers for introducing a surgical circular stapler into a patient. Various embodiments comprise a hollow flexible sheath that has a distal end and an open proximal end that is sized to receive a stapling head portion of the circular stapler therein. A rigid cap assembly is attached to the distal end of the hollow flexible sheath. The rigid cap assembly may be configured to selectively move between a closed position wherein a distal face of the stapling head is covered when inserted therein and an open position wherein the cap assembly may be withdrawn from around the stapling head and elongated shaft. A release arrangement interfaces with the rigid cap assembly such that upon an application of a release motion thereto, the rigid cap is movable from the closed position to the open position.