Matt Williams is a lousy manager. Everyone knows it.

But is everyone right?

Over the past two seasons combined, the Washington Nationals have been without Ryan Zimmerman, Wilson Ramos, Denard Span, Anthony Rendon, Bryce Harper and Jayson Werth — six of their best everyday players — for 565 combined games.

That’s an average of 94 lost games per man, almost all from injury. That may end up more than 100 games per man by season’s end because Span will miss 23 more and Zimmerman (oblique) easily could end up on the shelf, too. Only one player has been durable: shortstop Ian Desmond, who has missed just a dozen games.

So with as much or more lost time by everyday starters as any team in the National League in the past two years, how has the Nationals’ offense — assumed in the industry to be good when healthy, but never wonderful — done under Williams?

The Cardinals, Pirates and Cubs are dominating the National League and complicating the playoff picture, which rewards division winners over the best teams, usually a wild-card winner. Post Sports Live debates whether the MLB playoff system needs to be revamped. (Post Sports Live/The Washington Post)

Exclude the Rockies, who’ll be No. 1 in scoring both years. Their numbers are a mile-high joke. In fact, Colorado is dead last in NL scoring on the road this year.

Apart from Colorado, the Nats have scored more runs than any NL team in the past two years. The Nats are on pace to score 717 runs this year vs. 686 last year. Because MLB scoring is up a bit this year, the two Nats seasons, both decimated for months at a time by middle-of-the-order injuries, are essentially identical.

And that’s surprising. The Nats have been viewed as a pitch-first franchise during Williams’s two years as manager, not score-first. And the Nats don’t prioritize (and spend) for high-quality bats in reserve. Mostly, it’s make-do.

In 2014-2015, the Nats have scored 1,302 runs — 123 more than St. Louis. The closest team, the Dodgers (1,291), has infinite payroll and “starters” on the bench.

Normally, this would be explained, in part, by managerial acumen in constructing lineups that constantly compensate for an almost infinite variety of different Players Who Are Missing Today. For example, this season Yunel Escobar has battered Nos. 1-2-3-4-5-6, constantly filling different needs, and has batted .310 or better in all six spots.

Also, a manager’s in-game strategy — when to pinch-hit, when to use the running game, when to swing 3-0 — might explain how a constantly short-handed team could outscore everyone over a 301-game span.

But Matt Williams is a lousy manager.

The Nats’ starting pitchers have been a major disappointment this season, too, with a combined ERA of 3.79 entering Friday, 11th-best in baseball. Much of this is due to Williams’s lousy managing. He leaves starters in too long or he takes them out too quickly. “Everyone” in Washington knows this.

Yet last season, when almost exactly the same pitchers formed the Washington rotation — Jordan Zimmermann, Stephen Strasburg, Doug Fister, Gio Gonzalez and Tanner Roark — the Nats led the major leagues in team ERA (3.03) and were well ahead of teams like the Dodgers (3.40), who had a leg up in the race because Clayton Kershaw’s ERA (1.77) was insanely great.

Clearly, someone else must have been managing, motivating, aligning and hooking those starters last season because it couldn’t have been Williams. As one fan bellowed in a dead-silent Nats Park during a seventh-inning pitching change Wednesday night, “MATT, YOU IDIOT.”

Last season must have been a 162-game run of luck that enabled Williams to avoid “mismanaging” a rotation for a full year.

Inexplicably, the two new starters in the Nats’ rotation this season, Max Scherzer and rookie Joe Ross, have not been a problem. The starters who have failed this season are exactly the ones who anchored the staff last season. Yet it’s Williams’s fault that the same pitchers, none of them old and all of them working with the same coaches, who were the best in baseball last year have been utterly mediocre this year.

Williams’s worst flaw is his handling of the bullpen. He has no feel for it. He overworks his relievers mercilessly. Everyone knows that, too.

Yet last year the Nats had the second-best bullpen ERA in MLB (3.00), just ahead of the world champion Giants (3.01), whose deep bullpen, brilliantly handled by certified genius Bruce Bochy, was a key reason for their title.

Who managed that Nats’ bullpen last season? Or did that group just pitch a lot better?

This year, the Nats’ bullpen ERA is ninth in the NL at 3.68. One reason is Williams’s excessive overload — except there’s a problem with that, too. Just two teams in the NL have worked fewer relief innings than the Nats this season. How badly overworked can they be if 12 other NL bullpens have worked more?

When Williams has a functional bullpen, how much does he depend on it or overload it? Last season, just four NL teams had fewer relief innings than the Nats.

So, the bullpen has been lightly used both years. In ’14, which NL team was closest to the Nats in total relief innings? The Giants, with Bochy calling the shots.

But Matt Willliams is a lousy manager.

Maybe Williams isn’t a good motivator. But he has a veteran team that claims it shouldn’t need rah-rah or stuff-him-in-a-locker motivation.

Maybe Williams makes heat-of-moment decisions that violate situational stats. Down 8-7 on Tuesday, bottom of the ninth, leadoff man on first base, Bryce Harper on deck and a 3-1 count on Anthony Rendon, you cannot square around to sacrifice bunt because it virtually eliminates “ball four.”

After a 3-1 count, Rendon walks 32 percent of the time and gets on base 49 percent in his career. After 3-2, he ends up walking 31 percent and reaching base 50 percent. Think that one through again, Matt.

Maybe Williams is a rotten communicator. But how would we know? In public, he is one of the most cooperative and one of the most boring managers in the past 150 years. But those are his marching orders from General Manager Mike Rizzo and the Lerners: Be Sgt. Joe Friday: “Just the facts, ma’am.”

Everyone knows that Williams is a bad manager and should probably be fired. At least, for the past few months, that’s what I’ve heard from people that I have never seen inside Nats Park in my life. Now, that mood has gone viral, national.

Williams’s critics might be right. Back-to-back sweeps by the Mets within a six-week period are, in fact, enormous failures. A total emotional breakdown by most of the bullpen gets an “F” grade for any manager, whose job is to fix it. (Even if it’s impossible.)

Since last October’s playoffs, when Williams brought in Storen in Game 2, then didn’t use Storen (yeah, same guy), Tyler Clippard or Strasburg in the seventh inning of Game 4, Williams has been under a microscope.

I’d say Williams is about an average manager and a good man. Fire him if you want. No tears here.

Fire him if you need a scapegoat. (And teams sometimes need one.) Fire him if the players start blaming him, rather than themselves. (You can’t “lose the team” and keep the job.)

But don’t fire Matt Williams because you think it’s been proven that he’s a lousy manager.

Because that’s a lie.

For more by Thomas Boswell, visit washingtonpost.com/boswell.