How long does the Nationals' window to win extend?

Given the lengths of contracts, the aging of players and the overall circle of baseball life, it's popular to look at the Nationals and say they have a limited window in which to enjoy peak success.

What, though, is that window? Is it confined to one season? Two? Three? More?

Or has the window already closed shut? Remember, in the last year alone the Nationals have lost Ian Desmond, Jordan Zimmermann, Denard Span, Doug Fister, Wilson Ramos and Mark Melancon to free agency.

The reality is this: While it's easy to say the Nats' best opportunity to win a World Series might only last another two seasons before Bryce Harper inevitably signs with the Yankees, it's not nearly so cut and dry.

General manager Mike Rizzo actually has done a pretty good job of spacing out the expiration of his most important players' contracts, with one or two coming up per year in most cases. Some obviously are more significant than others, but the Nationals do have quite a few prominent players signed beyond 2018.

Let's look at this year-by-year, highlighting which players are due to become free agents at the end of each particular season.

2017
Jayson Werth
Gio Gonzalez (club option for 2018)
Oliver Perez
Chris Heisey
Jose Lobaton

2018
Harper
Daniel Murphy
Gio Gonzalez
Shawn Kelley
Derek Norris

2019
Anthony Rendon
Ryan Zimmerman (club option for 2020)
Adam Eaton (club option for 2020)
Tanner Roark

2020
Zimmerman
Eaton (club option for 2021)
Clint Robinson
Blake Treinen
Michael A. Taylor

2021
Max Scherzer
Joe Ross
Eaton
Sammy Solis

2022
Stephen Strasburg
Trea Turner
Pedro Severino
Koda Glover
Wilmer Difo
A.J. Cole

So the only prominent player entering his walk year now is Werth. This could be Gonzalez's final year in D.C., but the Nats do hold a $12 million option for him in 2018, which will automatically vest if the left-hander throws at least 180 innings this season.

All in all, that doesn't make 2017 do-or-die for the Nationals.

Things get more concerning in 2018, with Harper and Murphy due to become free agents at season's end. That would be a difficult one-two punch, if both end up signing elsewhere. But keep in mind that every member of the Nationals' star-studded rotation is under contract beyond 2018, so it's not like there's no long-term hope.

The potential losses of Rendon and Roark (and possibly Zimmerman and Eaton if the Nats don't exercise options on those two players) after the 2019 season is troublesome. But, again, we haven't even gotten to Turner, Scherzer, Strasburg, Ross and more.

What's the Nationals' true window for winning? It's not entirely clear. Yes, the task could get more difficult two years from now, but there's still a whole lot of talent locked up beyond that.

Best advice: Enjoy what you've got right now and don't stress too much about the future.