WASHINGTON D.C. — Roughly 3 ¹/₂ hours before the first pitch of Sunday night’s Game 5 of the World Series that was tied, 2-2, Nationals manager Dave Martinez delivered the news that could play a big role in deciding the outcome.

Before fielding questions in a pregame press conference at Nationals Park, Martinez revealed right-hander Max Scherzer, the scheduled starter, was scratched due to spasms invading the right side of upper body.

“Before we get started, I want everybody to know that Max will not start today. [Saturday] he had a little bit of spasms in his right trap and neck. They treated it. He woke up [Sunday] a lot worse,’’ Martinez said. “So Joe Ross will start today.’’

No disrespect to Ross, a 26-year-old right-hander who appeared in 27 regular-season games and one postseason game, he isn’t in Scherzer’s class because very few are. Scherzer is a seven-time All Star, has won three Cy Young awards and has 21 postseason appearances, including 17 starts.

According to Martinez, that Scherzer couldn’t post in a World Series game was an indication the problem was significant.

“If you all know Max, obviously he pitched with a broken nose, he’s been hurt before, he’s gotten through things. When he comes in and says he’s hurt this bad, he’s hurt,’’ Martinez said of the 35-year-old right-hander who won Game 1 when he gave up two runs and five hits in five innings. “I can tell you now he’s very upset. He wants to be out there with his teammates. But hopefully we can get him back here for either Game 6 or 7.’’

Martinez said the neck/trap issue wasn’t related to the back problems Scherzer dealt with during the regular season.

The manager also said Scherzer’s condition on Saturday led to him not using Ross and other relievers in case Scherzer couldn’t start Sunday night.

“Hoping that he’d wake up [Sunday] and feel a lot better,’’ Martinez said. “He didn’t.”

Because teams can drop injured players from the World Series’ roster and replace them, Martinez was asked if Scherzer would remain on the Nationals’ roster.

“Absolutely, yeah. We’re going to keep him on the roster. If this gets better in the next 24 to 48 hours, being that we have a day off [Monday], hopefully he’ll be available to pitch one of those two games,’’ Martinez said.

And what if Scherzer is fit enough to pitch Game 6? Could he start instead of Stephen Strasburg, who would then be available to start Game 7 if the Series gets to a final game?

“As of right now, I mean, I would leave Stephen starting Game 6 and if need be, depending on where we’re at, if Max could come in out of relief, he comes in. If we go to Game 7, Max starts Game 7,’’ Martinez said.

As for Ross, Martinez didn’t view him as a typical reliever filling an opener role.

“He’s starting the game. We’re going to let him go as much as he can go,’’ said Martinez who was hoping to get four to six innings out of Ross.

Of Ross’ 27 regular-season appearances, nine were starts. From Aug. 2 to Sept.29 he was used exclusively as a starter and went 4-1 with a 2.75 ERA. The Nationals went 7-1 in those starts.

Ross’ only postseason appearance this year was a two-inning stint in the Nationals’ Game 3 victory when he provided two shutout innings and one hit in a 4-1 win.