The Phillies had a bad trip, but those weren't hallucinations they were seeing Sunday. That was really the San Diego Padres — the last-place San Diego Padres — rolling over them to finish a series win. The Phillies won just two of their six games out west and will have a day off Monday to try to reset. The momentum they were building just a week ago seems to be slipping away. Their response will chart the rest of the season.

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—  Matt Breen  (extrainnings@philly.com)

Before September and October, Phils must survive August

Gabe Kapler has talked since spring training about playing into October. At the start of summer, Matt Klentak defined "contending" as playing meaningful games in September. But before the Phillies can reach September and October, they have to survive August. After an uninspiring West Coast swing, the final three weeks of August appear to be the crux of the season.

The Phillies left Citizens Bank Park last week in first place and flew back home in a virtual tie with Atlanta. They had a miserable series in San Diego, yet they hardly lost any ground in the division. But it's hard to imagine the Phillies' staying atop the East much longer if they continue to play like this.

They begin August's final three weeks with a two-game series against the Red Sox, who have won nine of their last 10 and have baseball's best record. It is not exactly an elixir for a listless team. They will play the Nationals six times, including two likely games against Max Scherzer. They will finish the month with the first game of a three-game series against the Cubs. The final three weeks of August will be a defining stretch.

The Phillies have been tested before. They lost three of four in Cincinnati earlier this month and then won five of their next six. That response kept them in first place. This response will determine what the rest of their season entails.

The rundown

Rhys Hoskins and Carlos Santana are stuck in a slump, as the two hitters combined to go 4 for 43 with 10 strikeouts during the six-game road trip. Gabe Kapler has batted the two second and fourth for most of the season as he believes those lineup spots are reserved for the team's two best hitters. Perhaps that could be changing.

"All things considered, it was probably the worst game the Phillies have played all season," Scott Lauber writes as he wraps up the team's poor finish to a poor trip. The Phillies gave up six stolen bases, made two errors, had a few more defensive lapses, and served up a grand slam to Freddy Galvis. The Phillies seemed to do nothing right against the Padres.

Freddy Galvis' grand slam Sunday was the finishing touch to a great series against his old team. Bob Brookover wrote before the series about how Galvis was the Phillies' best option at shortstop this season. The Phillies opted to trade Galvis for Enyel De Los Santos and instead received less than optimal production at shortstop before plugging the position with Asdrubal Cabrera.

Important dates

Today: Phillies are off.
Tomorrow: Nick Pivetta faces the Red Sox, 7:05 p.m.
Wednesday: Vince Velasquez closes two-game set with Red Sox, 7:05 p.m.
Thursday: Phils begin four-game series vs. Mets with doubleheader, 4:05 p.m.
Sunday: Phillies and Mets play in Williamsport, Pa., 7:10 p.m.

Stat of the day

If you think the Phillies are reeling today, how do you think the Nationals feel? They blew a three-run lead in the ninth inning Sunday and fell to the Cubs on an ultimate grand slam. Now that's a crushing loss. The Phillies last hit an ultimate grand slam — a walk-off grand slam hit when the team is trailing by three runs — on April 13, 1983. The batter: Bo Diaz. And the point of this tidbit: to share this great call by Harry Kalas. Hopefully, that makes your Monday a bit better.

From the mailbag

Send questions by email or on Twitter @matt_breen.

Question: Are we ready to call Carlos Santana a $60 million bust yet? — Hal M., email question

Answer: I'm not. Santana has been pretty poor since the start of July as he enters Monday with just a .647 OPS in his last 157 plate appearances. He has been lauded for his walk rate, but he has just 26 walks in his last 36 games.

But in the 53 games before that, Santana had a .915 OPS with 42 walks in 181 plate appearances. So he hasn't been awful all season. There's a lot of grumbling about Santana, but I find it hard to see the Phillies' reaching the playoffs without a productive Santana. He's shown this season that he can still be that kind of player. The Phillies have to hope this slump snaps soon. Also, ignore the money. The team is made up almost entirely of young players on club-friendly deals. Santana is one of the few veterans. He has to get paid. That's how baseball works.