Wisconsin Gov. Scott Walker called on NFL players to “get out there and stand up” for the national anthem shortly before 2018 regular season kicked off Thursday in Philadelphia.

In a series of tweets, the Republican governor urged players to “STOP this divisive political sideshow,” referring to the take-a-knee protests that have roiled the league since the 2016 regular season.

“The NFL season opener is tonight—players shouldn’t hide in the locker room or kneel,” said Mr. Walker. “They should stand up and show some RESPECT to our men and women in uniform—they fought and died for our country, the least we can do is stand for the anthem.”

Mr. Walker added that the protest “really is dividing the state and nation. There are plenty of other ways to speak out.”

NFL players should STOP this divisive, political sideshow tonight! Don’t hide in the locker room or kneel during the anthem… get out there and stand up. Put your hand on your heart. Show respect for Wisconsin’s men and women who fought and died for our country. 🇺🇸 — Scott Walker (@ScottWalker) September 6, 2018

Supporting those who refuse to do something that used to unite us as a state and a country — standing for the national anthem — really is dividing the state and nation. There are plenty of other ways to speak out. — Scott Walker (@ScottWalker) September 6, 2018

Ahead of the NFL season opener tonight, Tony Evers should make clear whether he is ok or not with players DISRESPECTING Wisconsin’s men and women in uniform — they fought and died for our country, the least we can do is stand for the anthem. 🇺🇸 — Scott Walker (@ScottWalker) September 6, 2018

The NBC Sports broadcast showed “The Star-Spangled Banner,” performed by Boyz II Men, and it appeared that all of the players on the field stood.

No players take a knee during national anthem. #ATLvsPHI — Derrick Rose (@DRoseTV) September 7, 2018

Mr. Walker, who’s seeking reelection in November, also challenged his Democratic foe, superintendent of schools Tony Evers, to take a position on the protests.

In response, Mr. Evers defended the players’ right to protest, tweeting, “I am proud to stand for the national anthem, and I am proud to respect our first amendment rights to peacefully protest.”

I am proud to stand for the national anthem, and I am proud to respect our first amendment rights to peacefully protest. Scott Walker wants to distract and divide us—anything to avoid talking about his record. That’s why we need a change. — Tony Evers (@Tony4WI) September 6, 2018

A Marquette University Law School poll released Aug. 22 showed Mr. Walker, seeking a third term, with a slim 46 to 44 percent lead.