Where Do David Hernandez and J.J. Putz Rank?

There's no doubt that one of, if not the biggest change in the Diamondbacks this year has been rock-solid stability in the late innings. David Hernandez and J.J. Putz have piled up 51 saves between them - no team in the majors has more this season and Arizona are an impeccable 78-0 in games where they have the lead after eight innings. The only blown save either man has had since June, was Hernandez's little eighth-inning meltdown in Coors last week. and the pair have combined to throw 118 innings with an ERA of 2.90.

But where do our pair rank among National League relievers? And how do they stack up in Diamondbacks history?

To find out, I looked at fangraph.com's WAR for relievers [I generally prefer bWAR as a measure of production for starting pitchers, but fWAR, being not just strictly based off ERA, has a lot of merits with regard to relievers. And, more importantly. was easily available in a handy Excel format]. For each team in the National League, I took the top pair of relievers by WAR, and combined their two numbers into a single stat. Note, I didn't pay any attention to the official designation of "closer", which is why the Marlins' Leo Nunez isn't listed, despite his 35 saves. He has accumulated only 0.2 fWAR, so isn't even close to being th best reliever on his own team.

Players who were traded between teams during the season were deemed to have all their WAR with their new employers, and the WAR number was based strictly off relief appearances, excluding any starts whether spot or regular. Here are the rankings for all 16 National League outfits:

1. Braves: 5.5 (Craig Kimbrel + Jonny Venters)
2. Cubs 3.5 (Sean Marshall + Carlos Marmol)
3. Brewers 2.8 (John Axford + Cameron Loe)
4. Giants 2.8 (Sergio Romo + Ramon Ramirez)
5. Diamondbacks 2.7 (J.J. Putz + David Hernandez)
6. Pirates 2.7 (Joel Hanrahan + Chris Leroux)
7. Phillies 2.5 (Ryan Madson + Antonio Bastardo)
8. Rockies 2.5 (Rafael Betancourt + Matt Belisle)
9. Cardinals 2.3 (Jason Motte + Fernando Salas)
10. Marlins 1.8 (Burke Badenhop + Steve Cishek)
11. Nationals 1.8 (Tyler Clippard + Drew Storen)
12. Dodgers 1.7 (Kenley Jansen + Javy Guerra)
13. Reds 1.3 (Bill Bray + Nick Masset)
14. Astros 0.9 (Wilton Lopez + Mark Melancon)
15. Padres 0.9 (Cory Luebke + Heath Bell)
16. Mets 0.8 (Bobby Parnell + Tim Byrdak)

Outside of the insane numbers by the assassination squad of Kimbrel and Venters for Atlanta, there isn't really all that much difference - less than three wins - between the best and worst. But all four of the teams who would make the post-season at the time of writing, have relievers ranked in the top seven. That's not just the National League either: the two teams on top of the same ranking for the American League are the probably play-off bound Yankees (4.7, David Robertson and Mariano Rivera) and Red Sox (4.0, Jonathan Papelbon and Daniel Bard). It's possible to win your division without a couple of dominant bullpen arms - the Tigers are at only 1.6 - but it's not common.

In most cases, the closer is usually there or thereabouts, in terms of being the best reliever on the team. 13 teams in the NL have them in their top two performers so far. The exceptions are the Rockies (Huston Street is ranked 5th on the team, 0.4 WAR), Marlins (Nunez, #5, 0.2 WAR) and Reds (Francisco Cordero, #4, 0.3 WAR). The Mets, despite having traded previous closer Francisco Rodriguez away, still find that his 0.6 WAR makes him the best reliever on the club this year, even now! At the other end, is it worth noting that four of the five teams whose closer is their best releiver by WAR, are occupying play-off spots? Is this cause, or effect?

The above rankings seem to pass the eye-test as well. The Braves have likely been the most dominant duo in the league, if not the majors, this season - I really do not fancy Arizona's chances if they face Atlanta and find themselves behind after the seventh inning. The next handful [including Putz and Hernandez] are close together, but I'd not like to face any of them with the game on the line, and they all have been more successful than not. But where do J.J. and David rank in Diamondbacks' history?

There are a couple of seasons where our set-up man and closer hadh comparable numbers to what we've seen this year. 2003 is the first candidate. That year, Matt Mantei and rookie Jose Valverde combined for 39 saves and a 2.39 ERA over 105.1 innings. Valverde moved into the closer's role after Mantei was injured, and they received valuable support from another rookie, Oscar Villarreal. He had an insane workload - his combination of 86 games and 98 innings hasn't been matched by any other pitcher since 1987, and he really hasn't been the same since. But in 2003, he had a 2.57 ERA, helping Arizona relievers rank fourth, with a 3.62 ERA - they've never been higher.

However, the greatest bullpen front-end in team history may be the 2007 version, starring what the 'Pit called the Four Relievers of the Apocalypse. They were Tony Pena (3.27 ERA), Juan Cruz (3.10), Brandon Lyon (2.68) and Valverde (2.66), all throwing at least 60 innings. Add in LOOGY Doug Slaten, who appeared 61 times with a 2.72 ERA, and you'll see why they went 30-19 and piled up 51 saves. Admittedly, the back-end sucked (Dustin Nippert + Edgar Gonzalez) and overall, this year's corps has a better ERA,, 3.70 vs. 3.98. But run-scoring is also way down. This season, we are only ranked 12th, while the 2007 version, despite the higher number, came 7th.

On the other hand, there are metrics where the 2011 bullpen are superior to 2007, in particular protecting leads. Here are the numbers in various categories for both versions of the Diamondbacks, as well as the 2001 National League averages and, for comparison, what the 2011 Braves have done:

The saves by this year's bullpen are most in the NL, and the save percentage is second to the Phillies (85%). I have not checked the W% in detail to see our ranking there - there's no single place to see them all - but our numbers are also better than Philadelphia's at all three points. On this basis, Hernandez and Putz would deserve a spot among the very elite of NL relievers, confirming their importance as vital pieces of the 2011 Diamondbacks puzzle.

[Saves and W% through Wednesday night; WAR and other numbers through Tuesday night]