With nearly all of the top free agents off the market, four of the game's biggest stars have been attached to trade rumors this offseason. Nolan Arenado, Mookie Betts, Kris Bryant and Francisco Lindor would be welcome additions to any team. Over the past four years, each member of that group ranks in the top 10 in FanGraphs wins above replacement. Last season, the group averaged more than 5.0 fWAR, with Lindor's very good 4.4 mark the lowest of the bunch.
We should acknowledge that the team trading one of these players would do so as a cost-saving measure designed to trim payroll, and thus would be expected to be worse in 2020. Given that the Red Sox, Cubs and Indians are all clear contenders, and the Sox and Cubs are two of the wealthiest teams in the game, these are unusual circumstances lacking in sound logic. However, if the team owner is calling for a reduction in payroll, then perhaps trading a star player close to free agency might be the best way to achieve that and get better in the near future, even if it isn't 2020.
Parting with any of these stars would be an incredibly difficult decision, but with the caveat above, here is an argument for and against trading each of the four.