LOS ANGELES -- Nationals right-hander Tanner Roark is starting what he said is the most important game of his career tonight, for Team USA against Japan in the semifinals of the World Baseball Classic at Dodger Stadium.
The winner will play undefeated Puerto Rico, a 4-3 winner over the Netherlands on Tuesday, in the championship game on Wednesday. The Japanese have been there twice, winning the first two Classic titles. The U.S.? Never.
:: 2017 World Baseball Classic ::
The semifinal and championship games are at 9 p.m. ET and will be broadcast live on MLB Network and MLB.TV.
The biggest game of Roark's career?
"So far, yes, I'd say so, considering the single-elimination nature of it," he said. "We're just going to go out, do our thing, have fun and give it our all."
If the U.S. avenges its 9-4 semifinal loss to the Japanese right here in 2009, Marcus Stroman will get the call in the final. Chris Archer, the top U.S. starter on the staff when the tournament began, will be pitching on his regular six days' spring spacing for the Rays against the Orioles in Sarasota, Fla.

Archer, who's slated to start Opening Day at Tropicana Field against the Yankees on April 2, was told on Sunday to remain with the Rays.
"I received a message this morning that I am no longer needed to pitch in the final round of the WBC. I will not be leaving camp as I thought," Archer tweeted.
Everything is fine, Team USA manager Jim Leyland said before the U.S worked out on Monday. There's no controversy. Nothing to see here.
"I think this is a good day to get this all out of the way and cleared up," Leyland said. "I want to make it clear to everybody, there are absolutely no issues with the Archer situation. In fact, it absolutely worked out really, really well."
Archer missed the second round of the tournament. He went back to the Rays and threw in a Minor League game on March 16, pitching 4 2/3 innings and 74 pitches against Double-A Chattanooga. He started the first game of the tournament against Colombia in Miami, pitching four perfect innings, striking out three and throwing 41 pitches, a matter that caught Leyland by surprise, he said on Monday.
Leyland had to use seven pitchers that game, which the U.S. won on an Adam Jones walk-off single in the 10th.

"The only confusing issue involving the Archer situation for me was the very first game, when he threw 40 pitches and it was four innings and I was assuming that he was going to throw the 65 pitches," Leyland said. "But evidently there was something, some pact between him and his club, the Tampa Bay Rays, that he needed to throw four innings or 65 pitches. That was the only thing that was confusing to me at all.
"So I want to make sure that everybody knows this. There is no controversy here. There are no issues here. We respect him. He wanted to play. He came out, he pitched great for us, and as it turns out, everybody should be happy."
The spacing issues began in the second round, when the U.S. wasn't scheduled to play last Thursday, Archer's throw day. Instead, Leyland started Drew Smyly, Stroman and Danny Duffy in the three games at Petco Park.
Smyly was taken off the roster for the Championship Round and was replaced by Giants closer Mark Melancon. Archer still remains on the U.S. roster.
"Unless you really have to add somebody, because of a slight injury or something, you dance the dance with the guy or girl who brought you," Leyland said. "This team, in a short period of time, has really become a close-knit group of guys. And I think that we've accomplished that one thing, no matter how this turns out."

Leyland's philosophy applies to Roark, who hasn't pitched since the second game of the opening round, relieving Stroman in a loss to the Dominican Republic. Roark worked 1 1/3 innings, allowing three runs on three hits and walking two. The Dominicans came from behind in that one.
The U.S. turned the tables on them this past Saturday night in San Diego, coming from behind to beat the Dominicans and move on to the Championship Round for only the second time in the history of the tournament.
Leyland said on Monday that he had no hesitation about starting Roark, whose only postseason experience is a relief appearance for the Nationals in 2014 and a Game 2 start against the Dodgers last October in the National League Division Series. Roark wasn't the pitcher of record in a 5-2 Washington win.
"Well, we piggybacked him in a game, and he struggled a little bit," Leyland said. "He threw 41 pitches. I think he's an outstanding pitcher. He's gotten the short end of the stick a little bit so far, to be honest with you, the way things worked out.
"But he deserves this start. There is no doubt in my mind about it. I feel great about it. He's been a trouper. He signed up for this event, and I'm pitching him. I feel very, very comfortable about it."
The World Baseball Classic runs through Wednesday. In the U.S., games air live exclusively in English on MLB Network and on an authenticated basis via MLBNetwork.com/watch, while ESPN Deportes and WatchESPN provide the exclusive Spanish-language coverage. MLB.TV Premium subscribers in the U.S. have access to watch every tournament game live on any of the streaming service's 400-plus supported devices. The tournament is being distributed internationally across all forms of television, internet, mobile and radio in territories excluding the U.S., Puerto Rico and Japan. Get tickets for the Championship Round at Dodger Stadium, while complete coverage -- including schedules, video, stats and gear -- is available at WorldBaseballClassic.com.