Don't be so sure Ruben Amaro is coming back, even though Phillies president David Montgomery told fans this week that the general manager "is not on the hot seat."

That's the word from ESPN baseball writer Jayson Stark, who chatted with Mike Missanelli Wednesday afternoon on the Fanatic (97.5 FM).

"I really would not expect [Montgomery] to say anything else publicly right now," Stark said. "David's all about showing faith in his employees ... and he's going to back Ruben, but I don't think this tells us anything either way about what they're likely to decide, about what he's likely to decide."

A shake-up of some sort, however, can be expected.

"They are certainly going to make changes in the organization," Stark said. "There's a lot of rumors swirling about all sorts of stuff below Ruben."

The shortage of top young talent on the big-league club has led to criticism of how the Phillies scout, draft, and develop players in their minor-league system.

"Would that be enough for the fan base? I don't think it would," said Stark, whose latest baseball book is titled Wild Pitches.

Such a course of action might even pressure the Phillies to give Amaro an extension, he said.

"What would the point be of bringing him back and not extending him? Then he'd have to twist through the same sort of stuff this winter, next season," Stark said.

Regardless, there are several reasons to be skeptical that Amaro will return.

For one thing, Montgomery might not have the final say. "How do we know the other owners are not going to get heavily involved in this?" Stark said.

Also, pressure from fans played a big role in 2005, when Montgomery fired general manager Ed Wade after the season.

"If fan revolt was a factor then, how could it not be a factor now?" Stark asked.

"I just think David isn't prepared to even think this through till after the season," Stark said.

Stark also said that the Phillies, despite denials, were one of five teams aggressively pursuing Cuban centerfield prospect Rusney Castillo. It might take a five-year deal worth $50 million to $60 million to land Castillo, who had "tremendous tools."

Of the Phillies, Stark said, "They need this player. They need all players."

Click here to listen to a podcast of the Missanelli-Stark conversation.

Contact staff writer Peter Mucha at 215-854-4342 or Follow @petemucha on Twitter.