Stephen Strasburg opts out of contract with Nationals. What now?

Days after being named World Series Most Valuable Player, Stephen Strasburg is in the headlines again – this time for opting out of his contract with the Washington Nationals.
This was mostly a formality for the postseason hero, who becomes one of the top players on the market this winter.
Here's everything you need to know about what's going on with Strasburg:
What's happening?
Strasburg is opting out of the four years remaining on the contract extension he signed with the Nationals in 2016.
So, is Strasburg a free agent now?
Yes.
Were we expecting this?
Very much so.
Does this mean he's leaving the Nationals?
No, not necessarily. The timing seems awkward because the Nationals just won the World Series, but they'll jump right into negotiations to bring Strasburg back and there's a better chance than not that he'll be in a Nationals uniform come spring training.
Could someone else sign him?
Yes, but – at the moment – there's no reason to think he won't work out a new deal with Washington.
What kind of contract could Strasburg get?
It will certainly be more than the $175 million total value of his last deal, probably somewhere in the $210-230 million range over six, seven or eight years.
I keep hearing "deferred money" as it pertains to Strasburg. What's that?
The Nationals organization has gotten "creative" with contracts in recent years to keep the present-day payroll down and Strasburg was no exception. Washington deferred – without interest – a huge chunk of Strasburg's money to annual payouts down the road, meaning that the actual present-day value of his existing contract was less than it appeared. Max Scherzer has similar deferrals built into the $210 million deal he signed before the 2015 season.
Can the Nationals bring back Strasburg and Anthony Rendon?
Probably. They declined franchise stalwart Ryan Zimmerman's $18 million option ($2 million buyout) for 2020 and he'll most likely come back at a much cheaper rate. The Nationals also declined Yan Gomes' $9 million option ($1 million buyout), so with just two off the books, there's more $20 million freed up for 2020. That said, the Nationals will want to avoid hitting the luxury tax threshold and may have to get similarly "creative" to do so.