Though free agency takes center stage at the beginning of each offseason, the trade market is arguably the winter's more important aspect. Last season, eight of the 10 teams who received the most Wins Above Replacement from players acquired in swaps made the postseason. That group includes the Boston Red Sox, Los Angeles Dodgers, and all but one division winner (the Atlanta Braves finished 13th). Free agency gets headlines, drafting and developing gets praise, but trades are the means through which contenders are built.

Of course, there's a reasonable explanation as to why free agency receives more attention than trades: It's easier to cover. We've known for years when Bryce Harper and Manny Machado would hit the open market. We have a fair idea of teams' payrolls. It's harder to uncover who will be on the trading block and which teams are willing to pay up in prospects to strike a deal.

Nonetheless, we wanted to provide an overview of our impressions of the trade market. Below, we've included players for every position except DH and reliever (for practical purposes since there's too many options). Keep in mind, inclusion doesn't mean these players are going to be moved -- it's possible we're misreading situations and they aren't even available. It just means that there's reason, in our opinion, to think the player could be dealt before next season begins. Inevitably, not every player dealt this winter will be on here. That's just the game, so be it.

Catcher

MLB: Miami Marlins at Tampa Bay Rays
Will J.T. Realmuto be with a different team in 2019?  USATSI

The market begins with J.T. Realmuto. His agent has said he's not open to staying with the Miami Marlins for the long haul, meaning the Marlins should be open to a deal this winter. Realmuto totes a middle-of-the-order stick and has two seasons remaining of team control. The Marlins ought to ask for the moon and a few satellites in return for their star.

Beyond Realmuto, there's uncertainty. Would the Kansas City Royals be willing to cash in Salvador Perez? If not, that could leave Francisco Cervelli (entering the final season of his contract with the Pirates) as the market's top option. The Boston Red Sox figure to move one of Sandy Leon, Christian Vazquez or Blake Swihart as well. 

The San Diego Padres should expect some phone calls as it relates to the status of Austin Hedges.

First base

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All Paul Goldschmidt does is hit. USATSI

You can bet most of the buzz will be about Paul Goldschmidt. The Arizona Diamondbacks are at least flirting with a teardown, and Goldschmidt is entering his walk year, making him an obvious candidate to go if general manager Mike Hazen decides it's time to reset. Jose Abreu is in a somewhat similar situation. The Chicago White Sox are trying to complete their rebuild, however, and making gains in 2019 might be enough to persuade them to keep him in tow.

The Philadelphia Phillies handed Carlos Santana a three-year deal worth $60 million. Now, they're reportedly shopping him around so Rhys Hoskins can assume first base. Santana is coming off a relative down year, but his on-base skills could make him appealing to a few contenders. It seems more likely that Santana gets moved than Wil Myers, seeing as how the Padres signed Myers to an extension that will see him get paid more than $66 million from 2020-2022. Myers hasn't been able to stay healthy or stick at one position for long.

Further down the market, the Tampa Bay Rays are expected to ship out C.J. Cron. He had a career-best season last year -- and has two seasons of team control remaining -- but is a fairly limited player overall. The Milwaukee Brewers could, in theory, move Eric Thames, too.

Second base

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We're getting tired of talking about Merrifield as a trade candidate. USATSI

Whit Merrifield has been considered the top available second baseman for a while now. The question is whether the Royals will actually move him. It seems silly, given Merrifield won't qualify for free agency until after the 2022 season. But he'll play next season as a 30-year-old and the Royals are a couple of years away from being competitive again.

Cleveland is certain to shop around Jason Kipnis, albeit likely to no takers. Ditto for the Marlins and Starlin Castro. That could leave someone like Joe Panik (depending on what Farhan Zaidi envisions for the San Francisco Giants) or Cesar Hernandez (if the Phillies decide to turn the keystone over to Scott Kingery or someone else) as the top second baseman available.

Shortstop

MLB: Philadelphia Phillies at Atlanta Braves
J.P. Crawford is still trying to establish himself in the majors. USATSI

We'll stick with the Phillies for a moment, because league sources indicated they shopped J.P. Crawford at the deadline. Formerly a top prospect, Crawford hasn't yet found stable footing in the majors as his 24th birthday nears. He could appeal to teams who still believe in his upside.

The aforementioned Diamondbacks have a pair of potentially interesting shortstop trade candidates. Nick Ahmed has an outstanding glove and showed more pop last season than normal. He's probably not the new Zack Cozart, but it might be worth finding out for sure. Ketel Marte seems likelier to stay in Arizona, given the long-term extension he signed. Still, if the Diamondbacks decide everything must go, then his combination of youth (25) and proven production (career 90 OPS+ in nearly 1,400 at-bats) makes him an intriguing player.

Two other names we'll throw out there: Jean Segura of the Seattle Mariners and Marcus Semien of the Oakland Athletics. If the Mariners strip down, Segura could bring back a nice haul. The A's won't be tearing apart their roster. Even so, trading Semien and his two seasons of team control could net them a pitcher while also opening up shortstop for Franklin Barreto.

Third base

MLB: Detroit Tigers at Tampa Bay Rays
Matt Duffy was productive in 2018. Might it get him dealt? USATSI

The Tampa Bay Rays have already traded one slap hitter who had a big 2018 in outfielder Mallex Smith. What about moving another in Matt Duffy? Duffy had a nice rebound after a pair of lost years. He's two years away from free agency and perhaps now at peak value. The Rays have more than enough infield depth to replace him should they choose to make a move.

We seem to keep mentioning the Diamondbacks and Phillies, so here goes nothing. Jake Lamb had a down 2018, but his combination of pop and on-base skills is appealing -- even if he has to be platooned against same-handed pitchers. Maikel Franco, who was up again in 2018 after a few down seasons, is all but certain to hit his 100th career home run in 2019. What uniform he wears while doing so could depend on the Phillies' pursuit of Manny Machado.

Depending on how serious the New York Mets are about competing, they could look to move Todd Frazier and/or Wilmer Flores.

Outfield

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David Peralta is a heck of a hitter. USATSI

Obligatory Diamondbacks section: David Peralta winning a Silver Slugger Award might've surprised you. It shouldn't have. Dude can hit -- especially right-handed pitchers. Steven Souza Jr. had a brutal season, but could make for an interesting buy-low candidate.

One of the few remaining veteran trade chips the Detroit Tigers have left is Nicholas Castellanos. He's never going to win a Gold Glove Award. He did, however, nearly hit .300 with 23 homers and 46 doubles last season. Castellanos is in his walk year, so expect him to be moved between now and next August to a contender hunting for a bat.

Again we'll mention the Brewers could move a hitter. This time it's Domingo Santana. He led the 2017 Brewers in OPS+, then had a poor 2018 as he was buried on the depth chart by Christian Yelich, Lorenzo Cain, Ryan Braun and Jesus Aguilar. Santana has a history of hitting, and he could make for a savvy pick-up. Billy Hamilton is the inverse of Castellanos and Santana. He can run, he can field, but he can't hit. The Cincinnati Reds figure to dangle him in talks for a pitcher. Then there's Kole Calhoun, whom the Los Angeles Angels are certain to shop around. Historically, he's been able to do a little bit of everything. Anyone interested is betting on a bounce back.

Starting pitchers

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Zack Greinke has so far been able to overcome diminished velocity.  USATSI

Have we mentioned the Diamondbacks might be rebuilding? Zack Greinke and Robbie Ray could, then, be the top starting pitchers available. Greinke has bled velocity in recent years, but has found success behind his athleticism, wits and deep arsenal. Greinke's situation is complicated by his contract, which states he'll earn more than $100 million over the next three seasons. Ray, conversely, has big-time stuff -- his fastball and slider in particular. Alas, his command dictates he's probably more of a mid-rotation starter than a frontline ace.

The market's dynamic shifts if Cleveland is serious about shipping out either Corey Kluber, Carlos Carrasco or Trevor Bauer. It's too early to tell if this is just Cleveland being Cleveland -- acknowledging their self-imposed budget limitations while feeling out the market -- or something more serious.

Beyond those names, the Tigers figure to again gauge interest in Michael Fulmer. The Baltimore Orioles, who traded almost everyone at the deadline, still have Dylan Bundy to take calls on -- provided, anyway, they ever install a new general manager. Then there's the Mets. We don't anticipate either Jacob deGrom or Noah Syndergaard getting dealt. But might Brodie Van Wagenen deal Zack Wheeler to shore up another spot on his roster?