Nationals reportedly offered Anthony Rendon seven-year extension, but he's expected to test free agency anyway

Rendon, 29, will be one of the best players available on the open market

The Washington Nationals will host the National League Wild Card Game on Tuesday evening against the Milwaukee Brewers. A loss would send the Nationals into what could be another pivotal offseason, as both third baseman Anthony Rendon and right-handed starter Stephen Strasburg could test the open market -- and perhaps depart, a la Bryce Harper last winter.

The Nationals, to their credit, have at least been trying to prevent one of the two from hitting free agency. General manager Mike Rizzo offered Rendon a seven-year deal worth between $210 and $215 million back in September, according to Barry Srvluga of the Washington Post. Rendon, obviously, did not sign and is expected to at least test the free-agent waters.

Here's more courtesy of Srvulga's report:

The offer, made in early September, is not expected to keep Rendon from exploring his value on the free-agent market this offseason. But the structure of the deal is an indication that the Lerner family, which owns the Nationals, wants to keep a star whom the organization drafted in the first round in 2011 and developed into an all-star.

As with most of the Nationals' big contacts, Rendon's pact would have included deferred money. But, as Srvulga notes, the structure of the deferred money would have been short-term in nature -- as opposed to the proposal the Nationals made to Harper last year, which would have seen him receive payments into the 2050s.

Rendon, 29, is expected to be one of the best free agents available this winter. He's coming off the best season of his career, as he hit .319/.412/.598 (153 OPS+) with 34 home runs in 146 games. Factor in his typically strong defense, and Baseball-Reference credits him with more than six Wins Above Replacement. He's been worth roughly four wins or more in each of the past four seasons, making him the 10th most valuable hitter in baseball over the period.

The Nationals' proposed extension would have paid Rendon less than the seven-year, $260 million pact that the Colorado Rockies handed Nolan Arenado back in the spring. Arenado is about a year younger than Rendon, but wasn't this close to free agency. To be fair, Arenado has accumulated almost five more WAR over the past four years, albeit almost entirely through defense -- an aspect that public metrics aren't always great at capturing. It seems like Rendon would desire a deal more in line with Arenado's -- especially considering his proximity to the open market.

It's unclear if the Nationals intend to make Rendon follow-up offers, or if Strasburg's (presumably) impending opt-out will force them to pick a side ahead of the offseason. For now, anyway, the Nationals would be justified in turning their attention away from the negotiating table and to the Brewers.