On Friday morning, the Mariners made what looked like a weird trade, shipping useful outfielder Seth Smith to the Orioles for less useful starting pitcher Yovani Gallardo, who is both not as good as Smith but also more expensive. Sure, the Mariners needed some more pitching depth, but they weren’t really rolling around in extra good outfielders, so subtracting Smith seemed weird.

Then, though, they made a second trade, this time swapping a starting pitcher for an outfielder, that made the pair of moves make a bit more sense. In the second deal, they shipped Nate Karns to Kansas City in exchange for Jarrod Dyson, who is a better player than Smith, so the series of moves actually resulted in an OF upgrade, with the impact to the pitching staff depending on what you think of Karns, who has both obvious strengths and minuses.

On the plus side, Karns has a 99 xFIP- in 265 big league innings, most of those coming in the rotation. His curve is a true outpitch, and with a solid fastball, he has a two-pitch combination that misses bats, so the foundation is in place for Karns to be a quality pitcher. The problem is that everything else needs a lot of work, as his his command is pretty lousy, and to this point, he’s shown a total inability to get batters out once they’ve seen him a third time in the same game; last year, batters hit .355/.417/.645 against him on the third or fourth time through the order.

Given his issues working more than 4-5 innings per start and his health issues, Karns is a prime candidate to be converted to the bullpen, and it wouldn’t be too surprising if the Royals turned him into a very good reliever, as they’ve done with other failed starters of late. The Mariners bullpen isn’t particularly great at the moment, so they could have used him in a similar role, but if you can swap a reliever for an above average starting outfielder making just a few million dollars per year, well, that’s a swap you generally want to make.

So even though I’m not sold on Gallardo as any kind of quality starting pitcher, I can see why the Mariners preferred the Gallardo and Dyson combination to the Karns and Smith combination. For the short-term, the new pair probably makes them a little bit better, and the team is clearly betting against Karns figuring things out and becoming a quality starter; if he does that in KC, then the Royals will come out well ahead.

But perhaps what is more interesting about these moves is not the marginal gains from swapping non-star pieces, but in the way the Mariners are trying to put together a winner. When you look at what they’ve done this winter, it seems now that Jerry Dipoto is, in some way, trying to build a west coast version of the Royals.

The Royals teams of the last few years had one very obvious strength; their outfield defense was insanely good. From 2014-2016, their outfielders combined for +135 UZR and +121 DRS, blowing away the competition, and propping up a mediocre pitching staff by turning every fly ball in the gap into an out. During the same span, the Mariners outfielders ran a -43 UZR and -71 DRS, as the remnants of the Jack Zduriencik era left the team with a bunch of bat-first sluggers.

Now, though, there’s reason to think the 2017 Mariners might have the best outfield defense in baseball, or at least be in the conversation.

Dyson, of course, was part of the Royals great wall of defense, and now he’s going to be roaming the fairly vast left field in Safeco. Taking a guy with a career UZR/150 of +21, with almost all of his playing time in center field, and sticking him in left makes him a likely candidate to be the best defensive LF in the game.

Dyson is only going to be playing left field because the team already has Leonys Martin as their regular center fielder. Martin might not be on Dyson’s level, but he’s at +9 UZR/150 in over 4,000 innings in center field, so he’s comfortably above average, if not quite in that elite tier.

Then, over in right field, the team will likely hand most of their innings to Mitch Haniger, whose upside we discussed when the Mariners made the Jean Segura trade. As noted at the time, Haniger was awfully impressive in center field in his limited action in the big leagues last year, and while you don’t want to read much if anything into Haniger’s gaudy UZR in 200 innings of work, there is some encouraging data in the Statcast numbers, which should be a bit more useful in small samples.

From Baseball Savant, here are the time and distance charts showing where Haniger’s catches came last year, and also where balls fell in in areas that he was responsible for.

The top chart is perhaps the more revealing one. Statcast tracked 10 balls that Haniger didn’t catch, but look at where they are on that chart; 8 of them were in the area that no one catches, one would have been a “highlight” catch if he made it, and one would have been a “tough” catch. Every single ball that was hit towards Haniger that was considered “routine” or “easy” was turned into an out.

Then, when you look at his catch chart, you’ll note that he actually did make a number of “tough” and “highlight” catches, so he wasn’t just sure-handed on balls hit right at him. While we don’t know how predictive this data will prove to be, it does support the idea that Haniger might be a quality defender, and like Dyson, he’s a CF moving to a corner, so he might rate particularly well compared to his new set of peers.

With three center fielders running around Safeco, the Mariners have the kind of outfield defense not seen in Seattle since the days when Mike Cameron, Ichiro, and Randy Winn were the foundation of perennial winners, even without giving the team traditional power from the corner outfield spots. Given the amount of Nelson Cruz, Mark Trumbo, and Seth Smith that the fans have seen out there lately, the change is likely going to be striking.

But like the recent versions of the Royals, the Mariners potentially great outfield defense will come at a cost. Steamer projects the team’s starting outfield to be worth something like 20 runs below average offensively, a big drop from what the team got from the guys they ran out there last year. With the offensive question mark of Mike Zunino behind the plate, Jean Segura’s likely regression, and an underwhelming first base platoon of Dan Vogelbach and Danny Valencia, the 2017 Mariners probably aren’t going to be a great hitting team, and will instead rely on their run prevention to help them win games.

Except, generally, you think teams counting on run prevention will load up on quality pitching. The Mariners, on the other hand, still have a lot of question marks on the mound. Felix Hernandez is coming off the worst year of his career, and might be more of an innings-eater than any kind of frontline starter at this point. Hisashi Iwakuma is 36 and his strikeout and groundball rates went the wrong way last year. James Paxton finally figured out how to throw strikes last year, but he’s never thrown more than the 120 big league innings than he managed last year, and durability has always been a problem for him. And after those three, it gets ugly.

Right now, we have the Mariners rotation projected as the 22nd best in baseball, ranking almost even with those same Royals they’re now trying to emulate. And that’s with a built-in expectation of a nice bounce back from Felix; if 2016 was more of a sign of the new normal, this group won’t even be that good. So, yeah, for this rotation to perfom well, the outfield defense is going to have to make them look better than they are.

Of course, the Royals other big key to success has been their bullpen, which has regularly been among the best in the game the last few years. Kansas City was able to win with an average offense and mediocre starting pitching because they dominated the end-game, holding onto every close lead they got. This is the part the Mariners haven’t yet re-engineered. Edwin Diaz looks like a potentially great relief ace, but he’s just one guy, and the rest of the group is uninspiring at best. If the Mariners really want to copy the recent versions of the Royals, they’re going to have find a few more good relievers to pitch in front of Diaz.

And, of course, another part of the recent Royals success was some magic, as they significantly outperformed their BaseRuns win expectations. If the speed-and-defense plan was a primary reason for that success, then perhaps the Mariners can copy some of that, but if the bullpen was the key to helping the Royals to win more close games than expected, then that’s probably bad news for Seattle’s ability to recreate that part of the formula. And that’s why we currently have the Mariners projected as an 82-80 team heading into 2017, putting them in line with other fringe contenders who need a bunch of things to go right to snag a playoff spot.

The outfield defense is probably going to be great, and the team will run the bases a lot better than they have in recent years. But winning with a thin line-up and a mediocre rotation isn’t the easiest thing in the world, and especially with a bullpen of one good guy and a bunch of random arms, the Mariners probably can’t count on repeating the Royals success. But given the moves of this winter, that’s clearly what they’re trying for.