Nick Castellanos signed a five-year, $100 million contract in the offseason to provide the Philadelphia Phillies with another lethal bat in the middle of the lineup.

For most of the season, Castellanos has struggled, and his power has been mostly nonexistent. His frustration bubbled over recentlywith a locker room spat with a longtime Phillies beat reporter.

However, he finally has some positive momentum after a strong road trip capped by a game-deciding home run ahead of the Phillies' homestand opener against the Washington Nationals on Thursday.

Castellanos smacked a go-ahead, two-run shot to deep center field in the eighth inning on Wednesday, sparking the Phillies to a 3-1 win over the Atlanta Braves. It was his first homer since June 30 and just his ninth of the season.

The big hit seemed cathartic for Castellanos, who enjoyed an All-Star season in 2021. He went 11-for-25 (.440) as Philadelphia went 5-1 on its trip.

"For me, personally, of course it feels great," Castellanos said. "But most importantly, the Phillies needed it."

The Phillies remain in contention for a playoff berth as they attempt to play October baseball for the first time since 2011, with their playoff drought the longest among National League teams.

"The morale is high in this clubhouse," Phillies catcher J.T. Realmuto said. "We feel really good about ourselves. We're confident. We just have to go out there and swing the bats well. We're pitching well. We're playing good defense. We feel like we're a team that could go on a run. I would definitely say that our best baseball is ahead of us."

Philadelphia made a number of moves just ahead of Tuesday's trade deadline, including the acquisition of starting pitcher Noah Syndergaard from the Los Angeles Angels.

Syndergaard (5-8, 3.83 ERA) is scheduled to make his Phillies debut on Thursday. The right-hander is 5-6 with a 3.15 ERA in 17 career starts against the Nationals.

Second baseman Jean Segura possibly could return to the Phillies' lineup. The two-time All-Star has been recovering from a broken right index finger on May 31 when he was hit by a pitch.

The new-look Nationals will look to avoid a second straight loss when they battle the Phillies.

It will the second consecutive game since a blockbuster trade sent Juan Soto and Josh Bell to the San Diego Padres for a bevy of prospects and players.

The Nationals scored five runs in the ninth inning on Wednesday but still fell 9-5 to the New York Mets.

The Nationals are 36-70, the worst record in baseball. They also own a woeful 9-38 mark against their National League East rivals.

Keibert Ruiz and Lane Thomas each hit solo home runs in the ninth on Wednesday, but the Nationals still lost. Again.

"We had some decent at-bats throughout the game," Washington manager Dave Martinez said. "But the last inning, they stayed deep, they started using the middle of the field. If we would have done that a little earlier, things would have been different."

Despite their record, the Nationals refused to wilt.

"I've always said these guys are relentless," Martinez said. "They aren't going to quit. They're going to play to the last out."

The Nationals will hand the ball to Paolo Espino (0-3, 3.78) on Thursday. In his Saturday start against the St. Louis Cardinals, the right-hander allowed seven hits and four runs in 4 2/3 innings.

Espino is 0-2 with a 6.33 ERA in eight career games, including five starts, against the Phillies.

Luke Voit, who was acquired in the Soto trade, will join the Nationals in Philadelphia. Martinez said that Voit likely would play first base or be the designated hitter.

Washington's Nelson Cruz (neck) was held out of the Wednesday game, and it was unclear if he would play Thursday.