The Phillies' biggest free-agent outlay this winter brought them a 36-year-old righthander pitching for his eighth team in five years. The allure of adding a $5 million pitcher such as Aaron Harang, though, goes deeper. The well-traveled veteran eats innings.

Relief pitching figures to be the strength of this year's Phillies. The more innings logged by starters such as Harang and fellow journeyman Jerome Williams, the less wear and tear in a rebuilding year on the young bullpen arms that are sure to factor into the team's future.

As the Phillies enter the first season of rebuilding, the back end of the bullpen features several pieces to build around. After the 2014 emergence of Jake Diekman, Ken Giles, and Justin De Fratus, late-inning relief is the one area of the roster already in great shape for the foreseeable future.

"The way we look at it is, in order for a team to be a winning team, you've got to have a good bullpen," De Fratus said. "We're just trying to solidify our piece of the puzzle."

Even if the front office finds a trade partner for $13 million-per-year closer Jonathan Papelbon, the bullpen should be a bright spot. The oldest of the touted trio is the lefthanded Diekman, who turned 28 in January. De Fratus doesn't turn 28 until October. Giles, the team's closer of the future, is merely 24.

Each is coming off his breakout season and entered this spring as much more of a known commodity. Unlike last spring, there was never any doubt all three would make the opening-day roster.

Giles' major-league call-up didn't come until June, and the hard-throwing righthander still managed to finish fourth in the voting for National League rookie of the year.

Diekman's 100 strikeouts ranked third among NL relievers and were the most by a Phillies reliever since Al Holland in 1983.

Forty-two of De Fratus' 50 appearances after his final call-up from triple-A Lehigh Valley were scoreless.

"I feel like once the starter gets pulled, there's a good shot the rest of the game will be zeros with whoever is pitching," Diekman said. "I think the most important part is we just want to pitch. I don't think a lot of us care where we pitch but once the starter's out, we just want to put up zeros until Pap can shut her down for good."

This spring had a different feel for each member of the trio. Last April marked the first time Diekman made an opening-day roster. De Fratus made his first last year, too, but still spent part of April and most of May in triple A. Giles began last season at double-A Reading before a meteoric rise.

The fact Diekman, De Fratus, and Giles broke out in the same season is probably not coincidence. The young relievers say they feed off each other. Mario Hollands, a 26-year-old reliever who this spring has battled an elbow strain, also emerged last year with a solid first half.

A long-standing familiarity exists among the pitchers. When one senses faulty mechanics while just long-tossing, the other gives it to him straight. They each take criticism from one another well, Diekman said.

"In the least corny way possible for me to say it," De Fratus said, "you start feeling like that's you out there [on the mound]. That's your brother out there. You're not competing [with each other], really. You're trying to get the job done."

They settled into their respective roles last season. De Fratus said he thought last year's bullpen clicked around the time Giles was promoted. Giles made a much-anticipated debut June 12, allowed a home run to San Diego's Yasmani Grandal, and then recorded a 0.99 ERA over his final 43 appearances. He struck out 64 of the 166 batters he faced.

Twenty one of Diekman's final 25 outings were scoreless. De Fratus put together an 18-inning scoreless streak that ended July 1.

"When everybody's grooving, it's arbitrary. You put in whoever you want. It doesn't matter," De Fratus said. "That's the feeling we had last year."

It's a feeling the Phillies hope the young arms carry over to this season and, more important, the years that follow.

Pen Pals

The Phillies bullpen features several young pieces to build around. Each member of the trio consisting of Jake Diekman, Ken Giles, and Justin De Fratus experienced breakout seasons in 2014.

Justin De Fratus, RHP

ERA: 2.39
Innings pitched: 52 2/3
Hits allowed: 45
Earned runs: 14
Strikeouts: 49
Walks: 12

Jake Diekman, LHP

ERA: 3.80
Innings pitched: 71
Hits: 66
Earned runs: 30
Strikeouts: 100
Walks: 35

Ken Giles, RHP

ERA: 1.18
Innings pitched: 45 2/3
Hits: 25
Earned runs: 6
Strikeouts: 64
Walks: 11

@jakemkaplan

Future Phils: Relief Pitchers

This is the one area in which the Phillies have developed well in recent years, with the emergence of Ken Giles and Jake Diekman as the late-inning relievers who set up closer Jonathan Papelbon last season. Papelbon has been on the trade block for a while and Giles is the closer in waiting, so the Phillies need to develop more solid bullpen arms.

Here are some candidates for the near and not-so-near future:

Andy Oliver. The Phillies used a Rule 5 draft pick and took Oliver off the Pittsburgh roster in the hopes that the 27-year-old lefty would be able to resolve control problems that have dogged him during his professional career. Likely opening-day destination: Phillies.

Edubray Ramos. If you're looking for the next Giles, this 22-year-old righthander might be your best bet. In addition to a searing fastball, the Venezuela native also displayed outstanding command last summer while posting a 0.82 ERA with three teams. Likely destination: Clearwater.

Tyler Knigge. The hard-throwing righthander excelled at Reading last season, but struggled trying to make the jump to Lehigh Valley. Likely destination: Lehigh Valley.

Elvis Araujo. The 6-foot-6 lefty never pitched above double-A with Cleveland, but the Phillies decided to take a flier and signed the 23-year-old Venezuelan to a major-league deal during the offseason. H impressed during his five big-league innings in spring training. Likely destination: Reading.

Seth Rosin. The 6-6 right-hander was acquired in the 2012 trade that sent Hunter Pence to San Francisco. He made his big-league debut in Texas last season against the Phillies before being returned to the team via the Rule 5 draft process. Likely destination: Lehigh Valley.

Elniery Garcia. The 20-year-old lefty from the Dominican Republic struggled in a relief role at Williamsport last summer, but finished strong as a starter in the Gulf Coast League. Likely destination: Lakewood.

Nefi Ogando. The 25-year-old right-hander struggled at double-A Reading last season and is a fringe prospect. But he provided some hope with a strong showing in the Arizona Fall League that he followed up with five scoreless innings in winter ball down in his native Dominican Republic. Likely destination: Reading or Lehigh Valley.

Colton Murray. The righthander from the University of Kansas rebounded from a difficult 2013 season and posted a combined 2.24 ERA in 47 games at Clearwater and Reading last season. Likely destination: Lehigh Valley.

- Bob Brookover