PEORIA, Ariz. -- The Padres signed Drew Pomeranz to a four-year deal in November, making an already solid bullpen even stronger. Evidently, that wasn't enough.

The Padres signed Pierce Johnson in December and brought back Craig Stammen in January, adding serious righty depth to the roster. Evidently, that still wasn't enough.

On the eve of Spring Training in February, Padres general manager A.J. Preller traded for Rays closer Emilio Pagán, giving Preller two of the sport's best end-of-game relief weapons in the same bullpen.

After an offseason spent adding to what already projected as a strong bullpen, Preller is hoping those moves are enough.

"Every single year, a bullpen is a tough thing to predict," Preller said last month at Cactus League media day. "We know these guys have a good track record. We like the guys we've acquired and the guys that are going to be competing for our team. It leads to competition, which is a good thing. It leads to some depth and an ability, hopefully, to withstand maybe an injury or somebody, from a performance standpoint, not doing exactly what we may predict them to do."

It's a numbers game. The bullpen is the most volatile part of any big league roster from year to year. The Padres have tried to combat that volatility with depth. Front office members have wondered only half-jokingly this spring where the Padres' Triple-A 'pen might rank among big league relief corps.

The Cactus League has only served to highlight that depth. The Padres' 2.75 bullpen ERA ranks first in all of Spring Training, and the 13 relief pitchers on the 40-man roster have combined to post a 2.11 mark this spring.

"There's a lot of talent," manager Jayce Tingler said. "Realistically, if everybody's healthy, there are probably going to be guys that are deserving to make a Major League team that maybe have to start in Triple-A. That's a very real scenario."

It's by design. The Padres bullpen currently projects to feature 11 relievers with sub-4.00 ERAs, according to ZiPS. One member of the front office put the number of big league-caliber relievers in camp as high as 17.

That might be a stretch. But the current bullpen crunch leaves certifiable relief weapons like Andres Muñoz and José Castillo seemingly on the fence. Luis Perdomo, Gerardo Reyes, David Bednar and Trey Wingenter -- upside options who haven't yet broken out in the big leagues -- are probably bound for Triple-A El Paso. The glut of relievers has also allowed for the Padres to transition prospects Michel Baez and Adrian Morejon back into starters, after they'd spent the second half of last season in the big league 'pen.

With Javy Guerra expected to make the team, there might be only one place available. (Maybe even zero, if Cal Quantrill makes the team as a swing man.) That has led to a fierce competition in the ‘pen, though the relievers themselves aren’t viewing it that way.

"When everybody's at a certain level, it pushes everybody else to stay at that level," Bednar said. "The competition factor -- everybody pushing each other to do better -- that's never a bad thing."

Kirby Yates, arguably the sport's best closer, will anchor the ninth inning, with Pomeranz and Pagán as set-up options from both sides. Matt Strahm, Guerra, Stammen and Johnson are expected to crack the Opening Day roster as well.

Among that group, it's hard to pinpoint where the regression might set in. But that's kind of the point: You don't see it coming. The Padres expect their current plans to change as regular-season attrition hits their bullpen. Then again, they're also optimistic that such a deep group of arms will lessen the effects of that attrition.

"Rest and health is probably the biggest thing," said Pagán, who was part of one of baseball's best relief corps in Tampa Bay last season. "One or two guys can carry a bullpen maybe for a year. But it's harder to replicate that success over an extended period of time.

"Whereas, the bullpen the Padres have created here, we're probably 10-12 deep. It's not just seven or eight. That should help keep guys from throwing too many days in a row, or throwing too many innings within a week or a month or anything. More than anything, it should just keep all of us fresh."

Tingler -- who might ultimately benefit the most from a lockdown bullpen as he navigates his first season as skipper -- put it more succinctly.

"The more depth you have, the better," he said. And the Padres think they have just enough of it.