The NFL has spent the first three weeks of the 2017 season embroiled in a controversy from which it cannot seem to escape.

Whether the stated issue is social justice, appreciation of our military, first amendment freedom, respect for the flag and the national anthem, or simply respect for each other, the sport appears to have alienated a significant segment of a national fan base that has grown tired of all the kneeling, arm-locking and posturing.

That’s certainly true in Baltimore, where the Ravens put themselves in the middle of the Colin Kaepernick situation early in training camp and found themselves back at ground zero last Sunday when they were one of the first teams to take part in an on-field protest after President Donald Trump crudely criticized players who have taken a knee during “The Star-Spangled Banner.”

Which is why you can expect to see protesters outside M&T Bank Stadium before today’s AFC North showdown between the Ravens and Pittsburgh Steelers. And you shouldn’t be surprised if you see another flat performance inside the stadium by a Ravens team that looked like it was on another planet — not just in another country — during last week’s blowout loss to the Jacksonville Jaguars.

No one should need John Harbaugh to explain that football is about focus. It is played with more emotion and intensity than any of the other three major professional team sports and it requires a level of commitment and concentration during the week of preparation leading up to each game that — apparently — is easily disrupted.

How else can anyone explain the unrecognizable team that showed up in London and struggled to execute in any phase of the game?

The Ravens returned to a more friendly time zone to get ready for one of their most important regular-season games of the season and Harbaugh is hell-bent on making sure nothing distracts from that effort.

“We’re getting ready to play a football game, and that’s what we do, and that’s all we can do,” Harbaugh said Wednesday. “The other issues are bigger than that; they are beyond our ability to address and deal with, but we can focus on the task at hand, and that’s our responsibility. That’s our job, and that’s what we’re required to do.”

Sounds great in theory, but how much can the players reasonably be expected to block out when fans are threatening to boycott the team and thousands have signed a petition calling on the Ravens to remove the statue of Ray Lewis that stands so prominently outside the north end of the stadium?

The statue isn’t going anywhere and this all will pass, but only if the players decide they’ve made whatever point they were trying to make (since it is a bit of a multiple-choice question) and the angriest fans realize that even the athletes they pay so much to see have a constitutional right to voice or display opinions others might not share.

The week has been full of speculation about what the Ravens, Steelers and the other 30 teams might do today and it’s clear the Ravens players have spent significant time discussing that among themselves. How much time and emotional energy has been expended is not known, but we saw how the Ravens played after last week’s attempt to show unity in the wake of Trump’s provocative comment.

Every team was grappling with the same issue and will be again, but only one team had to travel to London last week, return to face their chief division rival today and will be headed to the West Coast to face a tough Oakland Raiders team next week.

This is a critical juncture in the season for a team that badly needs to return to the playoffs this year. Maybe that pales in real importance next to the social issues that are being debated in between those games, but it is important to the fans who have supported the Ravens at no small expense over the past two decades.

Or, at least, the ones who plan to stick around.

peter.schmuck@baltsun.com

twitter.com/SchmuckStop

Read more from columnist Peter Schmuck on his blog, “The Schmuck Stops Here,” at baltimoresun.com/schmuckblog.