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02/21/12 8:00 PM EST

Hernandez feels at home in D-backs bullpen

SCOTTSDALE, Ariz. -- Don't be fooled by David Hernandez's quiet demeanor.

"David is kind of like the silent assassin," closer J.J. Putz said.

Though he somewhat flew under the radar, Hernandez was a key part of the unexpected success the D-backs had last year en route to winning 94 games and the National League West.

"Huge, c'mon," D-backs manager Kirk Gibson said when asked about the impact Hernandez had last year. "Eighth inning, he was money. He got stronger as the year went on, dependable. He's come in in outstanding condition. He's got a tremendous amount of ability, and he's going to have a huge impact."

The 2011 season was filled with new experiences for Hernandez.

For starters, well he wasn't starting, something he had done throughout his Minor League career with the Orioles. Then there was the fact that he was with a new organization and was spending his first full season in the big leagues.

Hernandez responded by appearing in a team-high 74 games while compiling a 3.38 ERA and 11 saves.

Good numbers to be sure, but he would have had an otherworldly 1.58 ERA if not for three appearances during the season in which he allowed 14 runs in just two-thirds of an inning.

Last spring, Hernandez still seemed to harbor hopes of one day returning to a starting rotation, but that no longer is the case.

"You always want to keep your doors open, but at this point I'm just really comfortable in the bullpen and I could see myself being down there for good now," he said. "I have no motivation for being a starter. I see what the starters go through with all that running and all those bullpens. I'd rather cut out the bullpens, and my bullpens can be in the game."

Hernandez gave credit to the training staff.

"Basically, the first time relieving for a full season you've got to prepare yourself and be able to stay ready day in and day out, which is a tough task," Hernandez said. "But Ken Crenshaw and the rest of the staff do a great job at just being able to work out the kinks in your arm and the tightness, just being able to keep us ready day to day."

When the D-backs acquired Hernandez from the Orioles, they viewed him as pitcher who had future closer written all over him. When Putz was on the disabled list last year, Hernandez stepped into the role and went 7-for-7 in save situations.

"I'd say there's a big difference," Hernandez said of pitching the ninth vs. the eighth. "I wouldn't say who you're necessarily facing makes it different, it's just the situation of ending a baseball game. Both teams battle for three-plus hours, and everything is more keyed in on their last at-bats. Just from the eighth inning to the ninth inning the game speeds up. The crowd is a little more into it and you have to take a second, step back and relax.

"I loved it. I guess it kind of fit my personality."

Hernandez's personality can be hard for others to get a handle on. He is quiet and shy, but inside he has a strong competitive streak and a good sense of humor.

"He'll drop one liners and have stuff to say that's pretty darn funny," fellow reliever Joe Paterson said.

Hernandez said that he has heard in the past that some teammates have thought he doesn't like them, because he is so quiet.

"In reality, it's just that I keep to myself," Hernandez said. "If I have something to say, I'll say it. I'll chime in, I'll chirp in every now and again. I'm easygoing, I guess."

And if he does one day assume the closer's role, do not expect to see any wild gyrations after strikeouts or wins.

"I'm not a [Jose] Valverde type," he said, referring to the former D-backs closer who's known for wild celebrations. "I won't be doing that out there on the field."

Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.