Successful baseball teams are made up of successful baseball players, and some of those players are better than others. The most precious commodity in all of baseball are superstar players -- be they pitchers or position players -- and acquiring one or two of those players makes it a lot easier to win a bunch of games over the course of a season.

But how do teams acquire players who provide tremendous overall value these days? Are teams still able to acquire premium talent on the open market, or does it require much more luck or planning to get a player capable of putting up five or more wins?

For the purposes of this (admittedly) quick and dirty exercise, I'm using very simple methods and filters. All I'm starting with is any position player who rated a 5.5 FanGraphs WAR or above during one season over the last five full seasons. That's it! This gives us everyone who I could consider having a true impact season during one year of their time.

Could you define an "impact" player as a player who provides less value in a single season, but spreads consistent, high value over multiple years? Sure. But the real rarity in baseball is the player who provides excess surplus value in a single year -- the player who has a true superstar season.

You can find all of those superstar seasons here, at this Google Sheet.

Anyway, this cursory look gives me 80 player seasons from 2010-2014, where a position player earned 5.5 fWAR or more. Of those 80 seasons, 54 of them were by a unique combination of player and acquisition type. For example, Mike Trout was above 5.5 fWAR three times: 2012, 2013, and 2014 ... but he was only acquired by his team once. Shin-Soo Choo had two seasons above 5.5 fWAR, once with Cleveland and once with Cincinnati, and that means two different acquisitions, so he counts twice.

You might be amazed by this, but the best way to acquire an impact position player -- at least over the past five years -- is through the draft.

What? You're not amazed?

52% of Impact Positional Players: Acquired Via MLB Draft

According to my list, 28 -- or more than half -- of those player-acquisitions that gave a team an "impact" season, came by just drafting the guy in question.

Moreover, if you look at the subset of guys I'd guess might crack the list for 2015, you see these names: Bryce Harper, Jason Kipnis, Todd Frazier, Josh Donaldson (new team), and Joc Pederson as the most likely guys to emerge. Out of those five, four were draftees, only save Donaldson who was traded again and would end up on my list for a second time.

30% of Impact Positional Players: Acquired Via Trade

After that, we've got 16 player acquisitions out of the 54 who were traded, the second-most viable way to get an impact position player. Shin-Soo Choo is the only guy to get acquired and provide impact via trade twice.

This tends to make sense to me, because not only does this include prospects acquired by trade before they become stars, but also those guys dealt at the deadline for impact, or by teams looking to make big splashy upgrades. But of these 16, only Adrian Gonzalez, Miguel Cabrera, Curtis Granderson, and the second Shin-Soo Choo trade really qualify as premium acquisitions among established stars.

Most of these deals were for prospects (Anthony Rizzo, Adam Jones, Michael Brantley) or guys who unexpectedly blossomed (Jose Bautista, Carlos Gomez, Chris Davis).

13% of Impact Positional Players: Acquired Via Free Agency

Third place goes to free agency, which is looking more and more like a terrible way to acquire an impact player. Only seven impact acquisitions were via free agency ... and two of them belong to future Hall of Famer Adrian Beltre. Perhaps more telling is that several of these FA acquisitions take on kind of a freaky, fluky tone. Beltre and Matt Holliday? Those guys we should expect impact from. Andres Torres and Aubrey Huff -- both serving their impact up for the 2010 San Francisco Giants? Not so much.

4% of Impact Positional Players: Acquired Via Amateur Free Agency

After that, it's my biggest surprise of the activity. Only two players (Robinson Cano and Jose Reyes) provided "impact value" over the past five seasons after being acquired as an amateur free agent. This just absolutely floored me. Sure, other guys on the list were, at one time, amateur free agents (Miguel Cabrera, Choo) -- but given the big bucks and big tools that come with international free agents, I expected better.

2% of Impact Positional Players: Acquired Via Rule 5 Draft

Finally, there's one guy who put up a 5.5+ fWAR season but was acquired through the Rule 5 Draft: Shane Victorino. Victorino is on the list twice -- also once for the Red Sox as a free agent signing -- but I'd hazard a guess that he's the last Rule 5 guy to put up a huge season. Or maybe Mark Canha's got a six-win season in him, who knows? The Rule 5 isn't exactly what it used to be.

So that's it. In the future, I'd like to expand this look to examine all the players who have a WAR Index of a certain level, as opposed to being beholden to just one method of determining value. And I'd definitely like to see where pitchers fall on the acquisition continuum.

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Bryan Grosnick is the Lead Writer for Beyond the Box Score, and a columnist at Baseball Prospectus Boston.