Farewell by the numbers for Mariano Rivera

John O'Boyle/The Star-Ledger/US Presswire

Is this the last season we'll get to watch MLB's all-time saves leader Mariano Rivera?

Yankees closer Mariano Rivera plans to announce this weekend that 2013 will be his final season in the majors.

If that's the case, he will end his career with more saves than any other player in major-league history, but what else can you say about the 43-year-old Yankees veteran?

Adjusting the standard

Best Adjusted ERA – MLB History

Of all the numbers from Rivera's career -- 1,051 appearances, 608 saves, a .210 opponent batting average -- perhaps none is more impressive than 206. That's Rivera's career ERA+.

ERA+ is ERA adjusted for the league and park, and allows you to compare players from different eras on the same baseline (100 is average, above 100 is above average).

How good is 206? It's the best in MLB history, and the next player on the list is Pedro Martinez, at 154, followed by Jim Devlin at 151.

Postseason state of mind

Most Postseason Saves - MLB History

Not only has Rivera piled up enormous postseason totals (his 42 saves are more than the next two players on the all-time list combined), but his rates have been outstanding in the playoffs as well.

His career postseason ERA is 0.71, the best in major-league history, and he joins Sandy Koufax (0.95) as the only players to pitch at least 50 career innings in the playoffs with an ERA under 1.00.

While his regular-season K/BB ratio is a sparkling 4.0, it's been even better (5.2) in the playoffs. Batters have managed a .210 batting average against Rivera in the regular season, but in the postseason, that figure dwindles to .176.

Hall pass?

As impressive as Rivera's credentials are, Hall of Fame relievers have been few and far between in MLB history.

There are only five pitchers in the Hall of Fame that started fewer than 100 games and had at least 50 saves: Bruce Sutter, Rich Gossage, Rollie Fingers, Hoyt Wilhelm. Of those, only one started fewer than 20 games, like Rivera: Bruce Sutter (300 saves, 0 starts).

That said, the 12-time All-Star and 1999 World Series MVP has Bill James in his corner. James developed several metrics designed to assess how likely a player is to make the Hall of Fame. One of them is Hall of Fame Monitor, created specifically for active players.

James assigned “points” for reaching various milestones, achievements, awards over the course of a player’s career. On a rough scale, 100 means there is a good possibility that the player will make the Hall of Fame and 130 is a virtual cinch.

Rivera has a score of 251, which is by far the highest among active players and is higher than that of Tom Seaver and Bob Gibson, among others.

Looking ahead

Rivera will try strengthen his grip on the record books this season as he goes for a 15th season with 30 saves.

That would break his tie with Trevor Hoffman for the most all-time. With an ERA under 2.00, Rivera would have 12 such seasons, breaking his tie with Walter Johnson for the all-time record.