Unanimity is a rare thing. There is always that one person who believes the Earth is flat, who prefers “The Godfather Part III” to “The Godfather,” who supports Pee-wee Herman for president.

Or who thinks Mariano Rivera doesn’t belong in the Baseball Hall of Fame.

On Tuesday, the Hall will reveal its new class of inductees, and Rivera, the superstar Yankees reliever, is certain to be among them. But there is a lot of curiosity about whether he will become the first player elected unanimously by the baseball writers, achieving something other shoo-ins have not.

Eight voters passed on Cal Ripken Jr., six on Nolan Ryan and 16 on Mike Schmidt.

In 1992, Tom Seaver came five votes short. In 1979, 23 writers said no to Willie Mays. “It’s an embarrassment to our association,” Jack Lang, the writers’ secretary and ballot-counter, said at the time.

In 1966, 20 voters decided Ted Williams wasn’t good enough. In 1962, Jackie Robinson fell 36 votes short of unanimity. Somehow, Joe DiMaggio didn’t get in until his fourth year of eligibility.