An apparatus for forming an anastomosis between adjacent intestinal sections of tissue is provided. The apparatus includes a circular surgical stapler having an anvil assembly with an anvil shaft and an anvil, the circular surgical stapler further having a tubular body portion with an annular knife and a body portion shaft selectively attachable to the anvil shaft; and a seal structure for deposition between the intestinal sections of tissue including a hub configured to engage attachment structure on at least one of the anvil shaft and the body portion shaft. The attachment structure is positioned so that the seal structure is located between the intestinal sections of tissue when the circular surgical stapler is disposed within the intestinal sections of tissue.