Yes, it was shocking to see Mariano Rivera serve up a grand slam. We all raced to the history books.
We were all amazed that he had only given up one previous grand slam in his career as a full-time relief pitcher.
And we shouldn't have been.
Outstanding closers -- even those on a level just below the Great Rivera -- don't give up grand slams. Joe Nathan has never allowed one, in 533 appearances. Jonathan Papelbon has allowed one, in 284 relief appearances.
Trevor Hoffman, who has pitched in 998 games (Rivera has 920 relief appearances), didn't allow his first slam until this year (Ryan Doumit of the Pirates, on April 27). Dennis Eckersley allowed one in 710 relief appearances. Troy Percival, Rollie Fingers and John Franco allowed two apiece, as have Billy Wagner and Francisco Cordero (all research done through baseball-reference.com ).
Rivera is great, the best ever at his job. But it's not the lack of grand slams that proves it.