The Mariners are trying something that has never been attempted before. In Jarrod Dyson, Mitch Haniger, and Leonys Martin they’re rolling out three legitimate center fielders that were center fielders last year. We’re in love with fly balls right now, but fly balls will not love Seattle this season.

There’s obviously some precedent for strong defensive outfields. The Cubs and Royals, for example, have both appeared in the World Series recently thanks, in no small part, to their ability to take away hits. But even if you stretch the definition of center fielder, something approximating Seattle’s current experiment appears to have been attempted only three times previously. And even then, it doesn’t appear to have happened exactly this way. While the three outfielders themselves don’t think it’s a big deal, there might be a few reasons no other teams have tried this.

All three of the starting outfielders in Seattle played 50 games or more in center last year. All three are likely to play at least 100 games this coming season. If that happens, the Mariners will be only the second club since 1956* to meet both criteria. The 2013 Indians were the first. They had Michael Bourn, Michael Brantley, and Drew Stubbs and in center.

*The earliest year for which a center-field designation exists in our data.

Already, though, you see the problem with drawing a straight line between these groups. Brantley was never considered a good center fielder by the defensive metrics, so you might take any of the three Seattle outfielders over him defensively. And although Stubbs and Haniger might have some commonalities, Bourn was also nearing the end of his career as a starter in 2013. If you’re talking about an outfield collective named Death to Flying Things, that Indians squad wouldn’t necessarily be your top contender to the 2017 Mariners.

But that year happened, so you have to bring it up. If you drop the requirements to 75 games started in the outfield in year two, two other teams join the fray.

The 1987 Mets, featuring Lenny Dykstra, Kevin McReynolds, and Mookie Wilson, technically had three center fielders. But McReynolds was no longer a center fielder, really, and one of those guys was also always behind some dude named Darryl Strawberry on the depth charts.

The 1976 Braves had Ken Henderson, and Rowland Office, and Jimmy Wynn. Wynn, though, was near the end of his career and only had one more year in him. Henderson was also close to the end of his time in the majors. Defensive numbers from the 70s aren’t gospel, but Mr. Office was never considered a good center fielder by Total Zone ratings.

If you want hope from history, you could look at the 2003 Mariners as representative of a few teams that have tried this with outfielders that were capable of playing center, but didn’t for team reasons. Ichiro Suzuki only played right field for that team, but he clearly had the defensive chops to play center, and that team added Randy Winn as a center fielder and put him in left, while Mike Cameron patrolled center.

So let’s say this is at least a rare thing, that three legit, in-their-prime center fielders are going to be on the field together most games for one team. What could go wrong?

It’s just one team, one time. Well, two times. Remember those 1987 Mets?

Hard to watch. To their credit, none of the three Mariners winced when I brought up the Carlos Beltran/ Mike Cameron situation. “We’re going to be out there calling for the ball, going to get the ball,” said an unfazed Dyson in camp. “We just have to communicate. Leonys Martin is good at that,” laughed Haniger. “It’ll be beautiful, man,” smiled a gregarious Martin.

Martin summed up the spring situation in Seattle camp best: “Communication is key. It’ll be a lot of fun, we’ll stick together and work on it a little bit. We need to trust each other, and here in spring training that’s the process. I’ve known Dyson for a little. Communication is no problem, not going to be a problem.”

Beyond potential collisions, there’s another reason teams haven’t tried this experiment before: offense. In the eternal tradeoff that is putting together a team, the Mariners have prioritized defense in the outfield, and it will cost them. Only two (rebuilding) teams have a worse projected offensive level from their top three outfielders this year.

Team Starting Outfield Offense Team OF wRC+ Padres 84.7 Reds 85.3 Mariners 89.0 Rays 95.3 Twins 95.5 Projected by Steamer, top three outfielders grouped by team

It doesn’t really get any better if you consider backups. Ben Gamel and Guillermo Heredia are both projected for less than league-average offense. Then again, they can both pick it, too. “We have depth,” said Dyson. “Someone goes down, we have someone to step up. Always good to have someone to go get it.”

This tradeoff between defense and offense isn’t some accident. “We had eight targets this offseason,” general manager Jerry Dipoto said this weekend at the SABR Analytics conference. “We got them.”

Perhaps it’s because they feel outfield defense has been undervalued. “We play in a ballpark and in a division that should enhance our ability to win games via defense, especially range in the outfield,” Dipoto said on that panel. “We play in a big ballpark where generally the ball hangs up in the gaps more than the others. We play in a division with at least three ballparks — in Anaheim, Oakland, Seattle — that play a little bit bigger than most,” he pointed out.

Park Factors by Division Division Average Home Run Park Factor NL East 97.8 AL West 98.8 AL Central 99.6 NL West 99.8 NL Central 102.2 AL East 103.2 SOURCE: FanGraphs Guts

The Mariners were fifth in fly balls as a staff last year, and they added the No. 2 fly-ball guy in Drew Smyly, so it’s actually more about the pitching staff than the parks. Dipoto said the same at the conference: “Maybe more importantly, we have a pretty fly-ball-centric pitching staff. That’s our pitching staff, so how do we maximize the value of a fly-ball pitching staff, and an environment that should be beneficial to a fly-ball pitcher with an outfield… quite frankly that, prior to this spring, wasn’t exactly rangy… Everyone we acquired, with the exception of Mark Rzepczynski, everyone we acquired was a fly-ball pitcher… We wanted to create a new paradigm for our club that was more built on defense and the ability to go run it down.”

This becomes a question about pitching, now, too. The staff may be built to counter the new swing in baseball that can take the low pitch deep but has problems with the high pitch. Perhaps they’ll throw more high fastballs this year — they were 12th in the league last year in average four-seam height in the zone — especially since they know their outfielders will track down anything that stays in the park.

And so the Mariners go into this full, team-wide experiment with their eyes wide open. They’re willing to make the offensive tradeoff — and risk a crowded outfield — in order to make sure their their defense is best suited to their pitching staff and ballpark. It’s not something that’s been done often in this scope before, and a couple of times when we’ve gotten close, it’s been just short of disastrous. That doesn’t mean it won’t work this time.

Thanks to Jeff Zimmerman for query help.