Bernstein's Toni Sacconaghi — a top Apple analyst — told CNBC's "Fast Money Halftime Report" that the company might disappoint on iPhone sales when it reports quarterly results Tuesday, but that could set the company up for a really big iPhone 8 cycle when consumers upgrade.

"The Apple story is much less about this year and more about iPhone 8, expected in September," he said.

iPhone sales make up around 70 percent of Apple's profits but as the smartphone market matures, the iPhone faces even more pressure on its margins, said Sacconaghi.

"I think it's difficult to believe you're going to get much growth from the iPhone," he said. "The question is, what will be big enough?"

The Apple Watch or TV could become important pieces of Apple's business down the line, Sacconaghi said. Though he has a sobering view on Apple, he has a $140 price target on the stock, and Bernstein has an overweight rating on the stock.

Sacconaghi said recently that there's "no doubt" that Apple's best days are behind it, and Tuesday he said that it's tough to forecast the company's prospects beyond the next nine months.



"Look, in nine months a lot can change at a dynamic company like Apple, but there certainly is a big question mark beyond that," he said.

