SAN FRANCISCO – One after another, Washington Nationals players expressed dismay that San Francisco Giants reliever Hunter Strickland would hit Bryce Harper with a pitch in apparent revenge for a dispute that took place three years ago.

Nationals manager Dusty Baker knows better. He has been around professional baseball for five decades and is aware some grudges last nearly that long.

So when Strickland drilled Harper on the upper thigh with a 98 mph fastball in the eighth inning of Washington’s 3-0 victory, inciting a brawl, it didn’t take Baker long to make the connection.

Baker may not have been a member of the Nationals franchise during the 2014 National League Division Series, when Harper twice homered off Strickland and yelled at him after the second blast, but he understood the genesis of the melee that suddenly erupted at AT&T Park on Sunday.

“I know he (Harper) took him deep in the playoffs a couple of times. (Strickland) probably took exception to that,’’ Baker said. “Baseball is a game where you don’t forget and you can hold grudges for a long, long time.’’

Strickland had not faced Harper since the Nats star crushed a game-tying home run in the seventh inning of Game 4 of that NLDS, a game the Giants went on to win to claim the series on the way to their third World Series championship in five seasons.

It didn’t take long for the hard-throwing right-hander to reintroduce himself to the 2015 NL MVP, firing his first pitch to Harper just below his hip. Harper immediately barked at Strickland, pointing at him with his bat. When Strickland didn’t back down, Harper flung his helmet at him – missing badly – and charged the mound.

Both players exchanged blows for a few seconds before Strickland was knocked to the ground by an onrushing wave of players and coaches from both sides, amid much pushing and shoving. Both players were ejected.

Harper said he didn’t go to the plate expecting any animosity from Strickland.

“I don’t want to go into a baseball game trying to fight somebody, especially when it’s in the past, so in the past it’s not even relevant anymore,’’ Harper said. “They won the World Series that year and I don’t even think he should be thinking about what happened in the first round. He should be thinking about wearing the ring home every single night. I don’t know why he did it or what he did it for.’’

Strickland, who had hit just four batters in 136 1/3 innings in his four-year career before the pitch to Harper, said his intention was merely to go inside. He acknowledged that’s not what it looked like, given their encounters from three years ago, the only times they had ever faced each other.

“I can see how that kind of stands in people’s minds, but that’s the past,’’ Strickland said. “Like I said, I left the ball over the plate a couple of times to him and he’s taken advantage of that. So obviously I’d rather miss in than over the plate.’’

It took three large teammates to drag the agitated Strickland off the field after the fracas, which featured a brief toe-to-toe between the combatants, both landing glancing blows to each other’s face.

Harper was ushered out to the dugout by teammate Ryan Zimmerman, who was in the on-deck circle when all hell broke loose.

Harper, a four-time All-Star before turning 24, has a reputation for brashness earned both through his words and his demonstrative on-field play. His style has made him a polarizing figure in the game, with veterans more likely to take issue with it.

However, Harper’s teammates did not hesitate to rush to his defense when the fight broke out.

“You can’t blame Bryce for what he did,’’ said Zimmerman, on his 13th year with the team. “I wouldn’t really enjoy getting hit for something … I don’t really know what he deserved to get hit for.’’

That may be a point major league baseball officials take into consideration as they assesses penalties for the incident, which will almost certainly include suspensions.

Giants manager Bruce Bochy pointed out Harper threw his helmet at Strickland, but it wouldn’t be hard to conclude who instigated the altercation.

“A baseball’s a weapon, and to be able to use that to his advantage, what do you want to do in that situation?’’ Harper said. “You never want to get suspended or anything like that, but sometimes you just have to go get ’em. You can’t hesitate. You either go to first base or go after him, and I decided to go after him.’’