The Uruguayan midfielder has made just two appearances since last March after he ruptured his anterior cruciate ligament in a 4-1 La Liga victory over Valladolid.
Cristoforo, who played in both legs of Sevilla's Copa del Rey victory over Sabadell, subsequently required further surgery on the issue.
Sevilla have confirmed that the procedure was a success, but the 20-year-old will miss between six and seven months of action.
"Sebastian Cristoforo was submitted to further surgery on his left knee in a satisfactory manner," read a statement on Sevilla's website.
"The operation consisted of replacing the lateral plasty and strengthening the knee.
"The intervention was successful and now the player will remain sidelined for a period of six to seven months before returning to the pitch."
