WASHINGTON >> Highlighting the pitfalls of beginning the baseball season amid a pandemic, Washington Nationals slugger Juan Soto tested positive for COVID-19 and was put on the injured list today, hours before the 2019 World Series champions were scheduled to face the New York Yankees on opening day.

Major League Baseball is the first of the four major North American team sports playing regular-season games amid the coronavirus outbreak, which is getting worse in some parts of the U.S.

“You feel bad for him. He’s a great player. The fans want to see him. And it affects our lineup,” Nationals general manager Mike Rizzo said.

“But what can you do about it?” Rizzo added. “You’ve got to play ball. … We’re going to have to win without our best guy. It’s a challenge.”

Soto, a 21-year-old left fielder who was a breakout star of last October after producing 34 homers and 110 RBIs during the regular season, will be sidelined until he can come up negative on two consecutive coronavirus tests.

“Unfortunately it hit us. And it hit us at a bad time,” Nationals manager Dave Martinez said.

Rizzo and Martinez said they got the news about Soto this morning.

“It hurts. … It’s bothersome, and then reality sets in,” Martinez said. “We’re in the middle of a pandemic and we’ve got to be awfully careful.”

Soto, replaced in left field by Andrew Stevenson in today’s lineup, already had missed the first two weeks of the team’s summer camp this month after being exposed to someone with COVID-19.

“He’s asymptomatic,” Rizzo said. “He’s following all major league protocols.”

Rizzo said the Nationals had done contact tracing to check whether other members of the organization had been exposed and “at this time, there’s nobody else unavailable.”

Every member of the Nationals was tested today but results weren’t expected before Friday, according to Martinez.

“Until we get those tests back,” he said, “we don’t know where we’re really at.”

Still, Yankees manager Aaron Boone said he wasn’t hesitant to play today’s game.

What he was wary of — and suggested that his players and coaches be, too — was being in too-close contact with the Nationals, particularly during pregame hours, when it’s customary to greet members of the opponent one knows.

“Normally, even in this environment, I wouldn’t really think twice about going over and just saying ‘Hi,’ keeping your distance. I’d be even more careful now, because obviously you don’t know what the fallout is from this,” Boone said. “So it is a reminder that these things can happen. Here it is, opening day, and one of the game’s best players, it happens to. It’s another reminder that it’s important to do all we can to keep ourselves safe.”

In other moves as Washington set its 30-man opening day roster, outfielder Emilio Bonifácio’s contract was selected, as were those of lefty Sam Freeman and righty Javy Guerra. Austin Voth, who entered spring training in a three-way competition for the lone unclaimed spot in the rotation, was listed by the Nationals as their fifth starter.

The other candidates were Erick Fedde, listed on Thursday’s roster announcement as a reliever, and Joe Ross, who opted out of the 2020 season.

Also today, Yankees second baseman DJ LeMahieu was reinstated from the COVID-19 injured list as New York set its roster before playing Game 1.

Yankees closer Aroldis Chapman and starter Masahiro Tanaka begin the season on injured lists — Chapman on the COVID IL, and Tanaka on the 7-day IL after getting hit in the head by a batted ball.

Boone announced on July 4 that LeMahieu and right-hander Luis Cessa tested positive for the coronavirus before traveling to New York for the team’s summer camp and said they were self-isolating at home.

LeMahieu signed with the Yankees before last season and hit .327, setting career highs with 26 homers and 102 RBIs. He was not in today’s starting lineup; Tyler Wade was playing second and batting ninth.

The Yankees also recalled infielder Thairo Estrada and righty pitchers Ben Heller and Michael King from the alternate site today. That trio is part of a group of eight Yankees making their first career opening day active roster, along with starting third baseman Gio Urshela, outfielder Clint Frazier, infielder Mike Ford, catcher Kyle Higashioka and right-hander Jonathan Loaisiga.

Ford, who went to Princeton and showed some power when he was called up by New York in 2019, posted a message on Instagram, calling today “a very special moment for me.”

“I will finally be able to look at my name on an opening day lineup card in the big leagues. I know the rosters are expanded and it is a strange season, but it is one I will always remember,” Ford’s post said. “If you told me my dream, making the opening day roster for the yankees, as a young kid in New Jersey would come true, I wouldn’t have believed you.”