Through history, many players have entered baseball's most hallowed hall. The list of players is numerous: 54 starting pitchers, 16 catchers, 18 first basemen, 17 second basemen, 10 third basemen, 21 shortstops, and 60 outfielders have plaques in the Hall of Fame. Even nine umpires have gained entrance to Cooperstown.
Some claim third base, or even catcher, is the most underrepresented position in the Hall of Fame.
However, only five relief pitchers have ever been elected: Hoyt Wilhelm, Rollie Fingers, Bruce Sutter, Dennis Eckersley, and Goose Gossage.
With reliance on the bullpen growing in modern times, that number appears set to rise in the next 15 years.
But by how much? And who is deserving of mention among the all-time greats?
After all, there's a reason only four such players have been elected.
The first reliever who deserves mention is the only one who seems to be an absolute lock for Cooperstown.
Since becoming the full-time closer in 1996, the Panamanian righty has dominated hitters consistently. His 206 ERA+ is the all-time record, and his 2.21 ERA and 1.002 WHIP are tops among active pitchers. Mariano is an 11-time All-Star, five-time World Series champ, and has placed in the top three of Cy Young Award voting three times.
By throwing his cutter almost exclusively, Mariano has blown away hitters to the tune of 553 saves, good for second all time.
In conclusion, Mariano Rivera has all the qualifications for a Hall of Fame reliever: a devastating pitch, an extended period of dominance, and solid playoff performance.
He has a very strong case for greatest reliever of all time, and he has a spot in Cooperstown already waiting for him.
The other relief pitcher who has a good chance at the hall is Trevor Hoffman. Being the all-time leader in saves and games finished helps.
However, Hoffman isn't the lock for Cooperstown that Mariano is. Despite sitting on the precipice of 600 saves, Hoffman has Rivera breathing down his neck. By the time he is eligible for Cooperstown, Hoffman could have very well fallen to second on the all-time list.
Unlike Rivera, Hoffman does not have a career long record of dominance - rather, he has two shorter stretches, from 1994-02, and from 2004-09. And Hoffman has never been as dominant as Rivera. He's only posted an ERA under 2.00 once, while Rivera is on his way to his tenth such season. Hoffman has also only posted a WHIP under 1.000 six times, while Rivera is on his way to an eighth.
I'm not saying Hoffman will be kept out of the Hall, but Lee Smith, known for having been the all-time saves leader before Hoffman, has been kept out.
Hoffman also doesn't have the playoff success of Rivera. In 12 postseason games, Hoffman has an ERA of 3.46, and a WHIP of 1.231.
When talking about active closers, the conversation often ends at Rivera and Hoffman.
However, Billy Wagner, who may be the greatest left-handed reliever of all time, doesn't get the credit he deserves.
Wagner has two of the three qualifications: a long dominant stretch, from 1999-05, and has a sizzling fastball that has reached 100 mph.
Perhaps the reason Wagner is so underrated is because he is so humble. Recently, after breaking Jesse Orosco's record for strikeouts by a left-handed reliever, Wagner called the record "stupid".
"I said 'We're getting our (butts) kicked, it's raining, let's go,' " Wagner said . "It's stupid. Who in their right mind makes a big deal out of doing something they're supposed to do in the first place? I'm out there pitching in a (bad) game; we're getting our butt kicked. It's not worth it to make a big deal out of that. That's embarrassing."
Perhaps it's his small stature. Despite being listed as 5'11'', Wagner still intimidates opposing hitters when he comes out to the tune of Metallica's "Enter Sandman".
During his most dominant stretch from 1999-05, Wagner had just one full season with a WHIP higher than 1.000, and he led the league in games finished twice. Over that span, he had an ERA+ of 196, culminating in a 293 ERA+ in 2005.
OUT (for now)
Just six months ago, I would have told you that Joe Nathan was paving his way to a spot in Cooperstown.
Since then, he's gone down for the season, and has gone from possibly the best closer in baseball to someone who started too late. After starting his career as a starter for the Giants, Nathan came to Minnesota by trade and started his career as a closer at age 29, far later than any closer in Cooperstown.
Since then, Nathan has been a rock, being as lights out as anyone in the game. His 2008 season is one of the best ever, as evidenced by his 316 ERA+, and WHIP of .901. If he had enough innings to qualify, Nathan would be second in ERA, ERA+, and third in WHIP, behind only Rivera and Hoffman.
However, after his season-ending injury, we have to wonder if Nathan will get those innings, or if he will come back as good as before. At his best, Nathan is one of the top closers of the last 15 years. If he can come back from injury like Trevor Hoffman did in 2004, his outlook looks good.
At the young age of 29, Jonathan Papelbon has put together what may be one of the greatest five year stretches in baseball history.
It started with what may be the most underrated rookie season ever. In 2006, Papelbon blew away hitters, to the tune of a 0.92 ERA and .776 WHIP, giving him a simply unreal 517 ERA+. He gave up 0.4 HR/9. Despite this, he finished second in AL Rookie of the Year voting, behind Justin Verlander.
The next year, although his ERA doubled to 1.85, Papelbon managed to lower his WHIP, to 0.771. Since then, Papelbon has been lights out. In 2010, he's posting his highest ERA, at just 2.91, but that doesn't diminish a career WHIP under 1.000, an ERA of 2.01, and an ERA+ higher than Mariano Rivera's.
Despite being known mainly for breaking the single-season saves record in 2008, Francisco Rodriguez is also one of baseball's premier closers.
Although he is just shy of dominant, Rodriguez is very consistent. From 2004-08, his ERA fluctuated around 2.20, and his WHIP hovered near 1.100. Although some people see Rodriguez as overrated for his 2008 season, he should be looked at as a strong, solid closer, who has an outside shot at Cooperstown, especially if he experiences further playoff success.
Keep An Eye On: Heath Bell, Brian Wilson, Huston Street, Carlos Marmol, Jonathan Broxton
Too Early to Tell: Joakim Soria, Andrew Bailey, Neftali Feliz