Dusty Baker on the Nationals’ 4-2 loss to the Phillies; Tanner Roark’s start, Chris Heisey’s homer...

Dusty Baker knows that as the defending NL East Champs, the Washington Nationals have a target on their backs from the start.

Opposing teams are looking to take a crack at the Nationals, who won 95 games and their third division title in five years last season, so Baker said his team has got to be prepared for other teams to bring their A-game.

“The whole season, every day is going to be a fight,” Baker told reporters after the 4-2 loss to the Philadelphia Phillies on Saturday, which was the Nationals’ third loss in five games against a team they dominated last season, going 14-5 against them in 2016.

“Especially when you’re the incumbent division winner,” Baker added, “then teams are going to get up for you and so it’s a matter for us to just keep fighting.”

Not to mention the fact that at this point, everyone is still in it, and some pitchers, like yesterday’s starter for the Phillies, Jeremy Hellickson, often have an advantage.

“Early in the season nobody’s spirit is broken,” Baker continued.

“And early in the season — Hellickson threw a heck of a game -- but it’s guys like Hellickson and [the St. Louis Cardinals’ Mike] Leake and those guys that change speeds that are the toughest to hit because your eyes still haven’t adjusted to the changeup speeds and you see it every year, these guys are the toughest to hit. They don’t necessarily strike you out, but they get you out.

“And so as the season goes on we’ll get more and more adjusted as these guys get more at bats, we’ll be better and better.”

Though they ended up losing Saturday’s game in the bullpen, the Nationals got a solid start from Tanner Roark, and a big hit from bench bat Chris Heisey, who was getting a start for the first time this season.

Roark went seven strong, holding the Phillies to two runs on four hits and inducing 11 ground ball outs from the 25 batters he faced.

“He was better,” Baker said. “He had better command of his sinker, his inside fastball and his slider and so he was battling his first two starts, but he was more in command as Tanner can be today, so hopefully he’ll keep getting better and get back. Today he was back to being Tanner.”

“He threw an excellent game,” the Nats’ skipper continued.

“We hit some balls hard, I mean, some balls extremely hard, and today was atom-ball Saturday, because i’m telling you, we hit some balls extremely hard and most of the time I thought some of those balls were capable of leaving the park.”

The one that did leave the park, was Heisey’s seventh inning home run off Hellickson, which tied things up at 2-2 a half-inning before Joe Blanton gave up a two-run homer that provided the margin of victory.

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It was Heisey’s first home run of the season and his 10th in 162 plate appearances in a Nationals uniform.

Baker was asked how the veteran slugger manages to do what he does, coming in cold and connecting for a pinch hit or starting occasionally and managing to come through.

“Well, he works hard,” Baker said. “He works hard at it. That’s why we played Heisey, so he would be confident and have some timing when we do really need him.

“He tied the game up today. He’s swinging well. He knows how to keep himself in shape and he works hard. And the non-regulars have to work hard. They have to work hard to stay sharp, and so we have to play them from time-to-time.”

Baker played a few of his non-regulars on Saturday, but it should be back to a more everyday-ish lineup for this afternoon’s series finale with the Phillies.