No general manager can hit on all of his trades and free agent signings. They all make mistakes. And Diamondbacks GM Kevin Towers is no exception.

He swung and missed quite a few times this year. Anyone remember Juan Miranda, Armando Galarraga, Melvin Mora, Russell Branyan, Geoff Blum or Zach Duke?

All moves that fans would like to forget and Towers wishes he could take back. But the Arizona Diamondbacks are in first place and Towers is a big reason why.

Not because of those moves that just plain and simple didn't work out. But for the moves that did work out.

How about Willie Bloomquist making $900,000 this year. Or JJ Putz on a two-year deal for a very reasonable $10 million.

Both great moves.

But the move that defines the Towers era so far is the trade he pulled off that brought David Hernandez to Arizona along with Kam Mickolio from the Baltimore Orioles for Mark Reynolds.

That trade often gets overlooked when discussions ensue about what were the key deals in the rebuilding of the D-backs.

The deals for Ian Kennedy and Daniel Hudson take precedent, and rightfully so, because they are starting pitchers who are anchoring the staff and keying the Diamondbacks resurgence. But none of this success is possible had Towers not worked his magic with the bullpen. And it's not like Towers took the job with an open checkbook.

The reason many of the above mentioned signings and trades didn't work out is because there wasn't much money to spend on better players and most times you get what you pay for. So Towers took a few chances on guys and had to release them. Such is life.

But he didn't miss on the one area he needed to succeed. The Arizona Diamondbacks had one of the worst bullpens in the history of Major League Baseball last year with an ERA of 5.74. In fact it was the 6th worst since 1953. Yes, it was that bad. The bullpen today is almost 2 runs better than it was last year. And Towers led the way to the complete overhaul of that problem area.

With little money to spend he secured a solid closer in Putz and has his future closer and current setup man in Hernandez.

In the Hernandez deal Arizona killed two birds with one stone. First, they rid themselves of the final two years of a bad contract on Reynolds (3 years, $14.5 million) that previous GM Josh Byrnes signed off on. Also, that eliminated an astonishing 211 strikeouts from their lineup. Second, they acquired a now 26-year-old flame thrower who has been as valuable to this ballclub as any player on the roster including Kennedy and Justin Upton.

The former Oriole with a 95-97 mph fastball has been nothing short of spectacular this season. He is 3-2 with a 2.77 ERA with 61 strikeouts in 51 innings and he has chipped in with 10 saves while Putz was sidelined or unavailable.

Hernandez has been so good that he has made Diamondbacks fans forget about names such as Juan Gutierrez, Blaine Boyer, Juan Noberto, Chad Qualls, Leo Rosales and Bobby Howry. Players who contributed to the infamous bullpen of 2010.

With Hernandez and Putz, Arizona has as solid a 1-2 punch to close out a game as anyone in the Majors and with Putz only having a year left on his contract the D-backs don't have to look far for their closer of the future. Hernandez may not get the fanfare of Upton or Kennedy but

I can assure you the Arizona Diamondbacks aren't in first place in mid-August had Towers not pulled off one of the great baseball trades of the offseason.