* Dudley sees Fed rate hikes as U.S. inflation weakness fades
* Apple down after muted launch for iPhone 8
* General Motors up after brokerage upgrade
* Futures down: Dow 15 pts, S&P 2.75 pt, Nasdaq 19.75 pts (Adds details, comment, updates prices)
By Sruthi Shankar
Sept 25 (Reuters) - U.S. stocks were set to open slightly lower on Monday, weighed down by a drop in Apple shares and heightened expectations of another interest rate hike this year following comments from a Federal Reserve official.
The central bank is on track to gradually raise interest rates as factors depressing inflation are fading and the U.S. economy's fundamentals are sound, New York Federal Reserve President William Dudley said.
Investors are also awaiting a speech by Fed Chief Janet Yellen later in the week for more guidance on the monetary policy.
"Investors would like to get more clarity as far as what the Fed is going to do as they move forward with the unwinding of the balance sheet and how they are going to move forward next year," said Robert Pavlik, chief market strategist at Boston Private Wealth in New York.
The U.S. central bank left interest rates unchanged in its September policy meeting, as expected, but signaled it still expects one more increase by the end of the year, despite a recent bout of low inflation.
Apple was down 1.26 percent in premarket trading. The stock clocked its worst weekly loss in over a year as the launch of iPhone 8 kicked off with a lukewarm response globally.
At 8:35 a.m. ET (1235 GMT), Dow e-minis were down 15 points, or 0.07 percent, with 23,887 contracts changing hands.
S&P 500 e-minis were down 2.75 points, or 0.11 percent, with 149,856 contracts traded.
Nasdaq 100 e-minis were down 19.5 points, or 0.33 percent, on volume of 32,836 contracts.
General Motors rose 1.67 percent after Deutsche Bank upgraded the automaker's stock to "buy", pointing to its autonomous vehicles, which could be ready for deployment within quarters.
D.R. Horton slid 3.7 percent after the No.1 U.S. homebuilder slashed by half its 2017 cash flow forecast from operations, citing delays due to recent hurricanes.
Allergan was up more than 1 percent after the drugmaker authorized a $2 billion buyback of its shares and said its chief financial officer would retire.
Chicago Chief Charles Evans and his Minneapolis counterpart, Neel Kashkari are scheduled to speak later in the day. (Reporting by Sruthi Shankar in Bengaluru; Editing by Anil D'Silva)