How did Phillies’ season go awry? They wonder, too

The Phillies have spent the last three or four weeks trying to determine what exactly happened in August that sent the team into a tailspin, general manager Matt Klentak said.

Their offense stalled and their starting pitching cracked as they lost control of first place and dug themselves into a hole that feels awfully deep with two weeks left in the season. Just before their stumble, the Phillies injected their young roster with three players before the trade deadline and then three more in early August.

Did that infusion alter the team's chemistry adversely? That, Klentak said, is "a very valid question."

"We come up with a theory, we test it, we try to reach some sort of conclusion: What happened in the month of August that we stopped winning baseball games?" Klentak said. "That being one of them. We test a lot of things. The best answer I can give you is whatever it is that caused us to go into a team-wide slump in August is not limited to one factor. It's not one thing. And if it was, we would have hopefully identified it and made that adjustment.

"We have theories about different things that may have contributed. It's probably some kind of combination of a lot of things. I will not sit here and tell you the chemistry changed in such a way that that is the reason we struggled. I don't believe that."

The Phillies had made a surprising run to first place when they brought on Asdrubal Cabrera, Wilson Ramos and Aaron Loup. That lead was starting to slip when they added Justin Bour in early August and they were beginning to fade when they added Luis Avilan and Jose Bautista at the end of the month. Perhaps the Phillies had just overachieved and it wasn't the chemistry that sent them spiraling but just a month of regressing to where they seemed to belong at the start of the season.

"We've looked into that, too," Klentak said. "And candidly, we thought about that as we were making trade-deadline decisions in July. How aggressive should we be? Is this real? And the reality was we were getting great starting pitching, a very solid and deep bullpen, and we were in first place. And how can we not go for it? How can we not make moves? We felt really bullish about that decision to add Ramos, Cabrera, Loup, and to double down on that in the month of August with three more additions."

The Phillies dismissed several minor-league hitting instructors last week as they aim to build a system in which the approach that is being instructed at the major-league level is something that is taught throughout the organization.

"There are some things offensively in the minor leagues that we'd like to change moving forward," Klentak said. "I'm not going to sit here and say bad things about the guys we let go. I like those guys. … As much as anything, it is tied to Joe Jordan stepping aside and we know we're going to be making a change in the development position and, I hate to say it this way, but sometimes when you have change at the top there are some other changes that follow."

>> READ MORE: Phillies' farm director Joe Jordan won't return, team says

As first reported last week by NBC Sports Philadelphia, the Phillies let go minor-league hitting instructor Andy Tracy, assistant hitting instructor Frank Cacciatore, triple-A hitting coach Sal Rende and high-A hitting coach John Mizerock. The Phillies also cut ties with minor-league field coordinator Doug Mansolino. The moves came shortly after Jordan resigned as director of player development.

The Phillies, under first-year hitting coach John Mallee, have used a "selective-aggressive approach" that instructs hitters to be aggressive on pitches that are thrown in the areas determined by the coaching staff to be favorable for a particular hitter. They are to be passive on pitches not thrown in the zones. They have added an emphasis on launch angle as they try to hit more line drives than ground balls. The approach, at least in year one, was not an overwhelming success.

"I think broadly, it's important at any level of instruction to stay current with what's happening and with the developments in baseball," Klentak said. "That's true at this level, it's true in the minor leagues, it's true with youth baseball. I'm not going to sit here and say that our group was or wasn't doing certain things because it's not that simple or it's not isolated to just that. But I do think broadly speaking in player development, we do want to create an environment of open-mindness and forward thinking."

>> READ MORE: Kapler backs hitting coaches despite underperforming lineup

Enyel De Los Santos pitched two scoreless innings of relief and seems to be a good candidate to pitch out of the bullpen next season. … Jake Arrieta will start Monday's series opener against Mets righthander Zack Wheeler. The Phillies will face lefthander Steven Matz on Tuesday and righthander Noah Syndergaard on Wednesday.