SAN DIEGO -- The Padres are not a complete team. Far from it, in fact. They have visions of contending for a Wild Card spot this season, but they have questions lingering at half of the places in their lineup and an unproven starting rotation.

But for all of their faults elsewhere, the Padres have built a pretty complete bullpen this winter. General manager A.J. Preller is hoping that might solve -- or at least mask -- a few of his other concerns.

On Friday, the Padres finalized a two-year deal with right-hander Craig Stammen, seemingly putting the finishing touches on a group of relievers that might project as the best in the National League. San Diego previously added Drew Pomeranz and Pierce Johnson to that mix, along with a handful of intriguing non-roster invitees to Spring Training.

Preller’s strategy to pursue a lock-down bullpen wasn't a haphazard one. The Padres didn't like the price tags on a number of aging free-agent starting pitchers this winter. They especially didn't want to take opportunities away from top pitching prospects Luis Patiño and MacKenzie Gore.

Instead, as multiple people in the front office put it, they followed the "Yankees model." Put another way: The Padres have built a deep bullpen with a handful of potentially elite arms. Ideally, that eases the burden on their rotation. If back-end starters like, say, Joey Lucchesi or Cal Quantrill are only asked to go five innings, that might be the best way to maximize production.

So how exactly do you build a great bullpen? And do the Padres have one? Let's take a look at the factors in play:

Start at the back end

Is a great bullpen really a great bullpen without a lock-down closer? The Padres, of course, might have the best closer in the sport right now. Kirby Yates is coming off an utterly dominant season in which he posted a 1.19 ERA, while striking out 15 hitters per nine innings.

To many across the sport, it seemed like an age-32 breakout season. At the very least, 2019 served as the year where the rest of the baseball world took notice of Yates. But the veteran right-hander has actually been dominant for a while now. He owns a 2.31 ERA in three seasons with the Padres and his 14 strikeouts per nine is the highest mark in franchise history. Yates has basically been a clear-cut top-five reliever since he started throwing his splitter regularly.

That's not to say Yates isn't prone to the volatility that comes with relief pitchers. A year ago, Blake Treinen was one of the sport's best closers, and he was non-tendered by Oakland earlier this offseason after posting a 4.91 ERA in 2019 (up from 0.78 in '18).

But Yates has been consistently excellent since adding his splitter to his arsenal. Opponents are hitting .141 against the pitch, and they've whiffed at 41 percent of them. There's an easy way to explain Yates' late-career success -- and his splitter isn't going anywhere.

Load up on big-time arms

Maybe José Castillo's injury woes flare up again. Maybe Andres Munoz's Minor League walk issues show up. Maybe Javy Guerra's mechanics aren't fully ready for the big leagues after his transition from shortstop to the mound. Maybe prospects Adrian Morejon and Michel Baez aren't quite ready (or they're deemed better fits in the rotation).

Those are all possibilities. There's downside to all of those arms. But that isn't the point. The point is this: The Padres have loaded up on so many big-time arms, they're likely to hit on at least a couple. If they do, they might have some elite support for Yates and Pomeranz at the back end.

Castillo boasts a fastball in the upper 90s and a near-unhittable slider (42 percent whiff rate). He's an easy choice as the top middle-innings lefty. Muñoz, meanwhile, takes it a step further, with a fastball that cracks triple digits and a slider that buckles knees. He could be a perfect seventh-inning righty.

Guerra, Morejon and Baez bring upside, as well. Both Trey Wingenter and Gerardo Reyes flashed dominant stuff last year, too, but they've yet to put it together in the big leagues.

It’s unlikely that all seven pitchers listed above reach their full potential in 2020. But if two or three of them do, the Padres would own a seriously high-octane bullpen.

Complement those big-time arms with reliable ones

If that list represented the entire group of Padres relievers behind Yates, their 2020 bullpen would qualify as a mystery. But Preller guaranteed himself a bit more certainty in his 'pen with some of his offseason decisions.

The Pomeranz signing raised a few eyebrows, given the length (four years) and dollar figure ($34 million). But there's no question that Pomeranz makes the Padres' bullpen better instantly. And while he slumped to a 4.85 ERA last season, he spent most of it as a starter. In relief, Pomeranz owns a 2.72 ERA with a .596 opponents' OPS in 102 career appearances. That's a pretty safe bet, at least as relievers go.

Preller also shored up the bullpen by bringing back Stammen, who was shaky at times last season but has been mostly reliable over three years with San Diego. He's posted a 3.06 ERA since coming to the Padres in 2017. There would be obvious cause for concern if Stammen -- a 36-year-old righty without putaway stuff -- continued as Yates' primary setup man. But if Stammen serves as a fifth- or sixth-inning fireman, he’s a pretty strong option for that spot.

Then there's Matt Strahm, who has been shuttled between the bullpen and the rotation. He appears slated for a more permanent return to the 'pen this year. Strahm has been nothing short of dominant as a reliever, owning a 2.71 ERA with 144 strikeouts in 108 appearances. Strahm can work multiple frames and has been effective against both lefties and righties, making him the perfect bridge to the back end.

Build legitimate depth

To recap, the Padres have Yates and Pomeranz at the back end of their bullpen. They'll give Castillo and Muñoz a chance to form a lefty-righty duo to help cover the late innings. Meanwhile, Strahm and Stammen are poised for middle-inning roles, picking up the slack for a young rotation.

On the surface, the Padres have constructed a clear plan for their 2020 bullpen. Thing is, bullpen construction never goes according to plan. And that's where the rest of Preller's decisions come into play.

The Padres signed right-hander Pierce Johnson to a two-year deal after he'd spent a dominant season with the Hanshin Tigers in Japan. He held onto Reyes, Wingenter and Luis Perdomo, as well. It wouldn't be wise to enter a season relying on any of those four pitchers to fill major roles. But the Padres aren't. They're just asking them to compete for a place on the roster -- and maybe earn their way into a bigger spot.

Beyond that group, the Padres inked Kyle Barraclough, Chih-Wei Hu and Jimmy Yacabonis to Minor League deals. They're inviting other intriguing arms -- like Dauris Valdez and Steven Wilson -- to big league camp. When those pitchers are your 15th through 19th best options, you've presumably built yourself a nice contingency plan.

In short: The Padres’ big-time arms give their bullpen a huge ceiling for 2020. But their depth gives the bullpen a very high floor, as well. New manager Jayce Tingler should have plenty of options at his disposal.