Baird's semiconductor team recently suggested a 20 percent cut in procurement orders based on its supply chain conversations, Power wrote in a research note. He now expects there to be 234.7 million iPhone units sold in fiscal 2016, down from his original 243.8 million forecast.
"There was enough noise in the marketplace that it made sense to be a little more cautious, at least on the March quarter shipment number," Power told CNBC.
To be sure, the iPhone still has a solid outlook longer term, Power said. With new opportunities like the Apple Watch and Apple Pay, on top of expanded possibilities for Asia, the tech giant still has a "high-quality balance sheet," according to Power.
"Certainly, longer term, I think there are still opportunities for them to continue to take share," Power said. "You know, on the other hand, the smartphone market is maturing, as we know. So for them to continue to gain share is going to get increasingly difficult over time. "
Shares of the tech giant rebounded from the earlier fall and were up slightly at $111.01 midafternoon Wednesday.
Apple did not immediately respond to CNBC's request for comment.
Disclosure: Apple is an investment banking client of Robert W. Baird & Co.