File- This Nov. 18, 2012 file photo shows New England Patriots tight end Rob Gronkowski on the sidelines in the second half of an NFL football game against the Indianapolis Colts in Foxborough, Mass. Gronkowski has undergone back surgery, Tuesday June 18, 2013. The operation was performed on Tuesday by Dr. Robert Watkins and was successful, said Drew Rosenhaus, Gronkowski's agent. (AP Photo/Michael Dwyer, File)