What free agent starters might the Nats consider this winter?

The Nationals' No. 1 need this winter, arguably, is a starting pitcher. They've got four well-established guys set to return next season in Max Scherzer, Stephen Strasburg, Gio Gonzalez and Tanner Roark, but they have no obvious choice to be the fifth starter.

Joe Ross, who held that job for most of the first half of the 2017 season, had Tommy John surgery and won't be back until July at the earliest. Edwin Jackson, who held that job for most of the second half of the 2017 season, is a free agent and wouldn't appear to be the Nats' top choice in 2018.

Erick Fedde is the future, but the top pitching prospect underwhelmed in the first three starts of his big league career and then was shelved for all of September with a forearm strain. The Nationals can't commit to the 24-year-old yet, not until he re-establishes himself at Triple-A over a prolonged stretch.

A.J. Cole, though he probably exceeded some expectations this year, still is viewed by most as rotation depth that can be called on in-season when needed. However, here is one hang-up with Cole in 2018: He'll be out of options and thus can't be sent to the minors without first clearing waivers.

So all of that leaves the Nationals needing to look elsewhere for rotation help this winter. The easiest place to find that kind of help, of course, is the free agent market. But here's the problem: The handful of elite starters cost a fortune and are in high demand, the next tier of middling starters probably aren't worth the long-term contracts they'll be offered and the lower tier of cheaper options isn't particularly enticing.

There really are only three big names out there right now: Yu Darvish, Jake Arrieta and Shohei Ohtani. The first two are established major league stars and are each going to get nine-figure contracts. (The Nats already have two of those pitchers locked up long-term in Scherzer and Strasburg. Are they willing to add a third?) The last one is this winter's most hyped Japanese import, a budding star who is selling himself as a two-way player who can both pitch and hit.

Ohtani is awfully intriguing, but it must be noted here that the Nationals have never signed an Asian player who had yet to appear in a major league game. Whether you agree with the strategy or not, their (unofficial) philosophy has viewed those players as too big a risk given the money that must be put down on the table upfront.

What about the second tier of free agents? There are some names that make sense from the Nationals standpoint. The problem is that most aren't going to be solid values.

Alex Cobb and Lance Lynn are solid, middle-of-the-rotation starters who are both in their 30s, have a recent history of injury, have stats not all that dissimilar from Gonzalez and are likely to get four- or even five-year contracts. If either could be had on a short-term deal, it would make perfect sense. But a long-term deal? That's a sizeable risk.

CC Sabathia could be had on a short-term deal, and he would make some sense from the Nationals' standpoint. But the expectation around the sport has been that the 37-year-old lefty is most likely to return to the Yankees for his 10th season with the franchise.

Tyler Chatwood? Jaime Garcia? Andrew Cashner? Jason Vargas? We're starting to delve into less-than-appealing territory here, with middling pitchers who still figure to get paid more than $10 million a year.

Chris Tillman or Jeremy Hellickson? Those are previously effective starters coming off ragged seasons. Either could pan out as a classic buy-low pickup, but are the Nationals interesting in taking that kind of risk on their No. 5 starter?

You can see where all of this is going. If the Nationals are going to turn to free agency to fill their rotation hole, they're either going to have to go all-in on a $100 million stud, overpay for a second-tier guy or take a big risk with a third-tier choice.

Which is why Mike Rizzo's best option might well be the one he has turned to several times before when in need of rotation help: the trade market. Remember how the Nationals acquired Gonzalez prior to the 2012 season and how they acquired Doug Fister prior to the 2014 season?

These kind of deals don't come easy. The Nationals gave up four prospects for Gonzalez, all of which reached the majors. They gave up three young players for Fister, with Robbie Ray eventually turning into an All-Star for the Diamondbacks.

The Nats farm system isn't what it used to be, especially after last winter's trade for Adam Eaton (who required three pitching prospects). They don't have a ton of guys to offer another club for a quality starting pitcher.

But given the state of the free agent market right now, it might be their best hope to find that elusive No. 5 starter.