* Futures down: Dow 14 pts, S&P 3.25 pts, Nasdaq 3.25 pts
By Yashaswini Swamynathan
Oct 11 (Reuters) - U.S. stock index futures were slightly lower on Tuesday as oil prices fell and investors braced for quarterly corporate earnings season.
* Oil prices fell 0.56 percent, a day after hitting a one-year high as investors questioned whether a deal to cut output would be enough to reduce the supply glut.
* The third-quarter corporate earnings period unofficially kicks off, with aluminum producer Alcoa reporting results.
* Overall earnings of S&P 500 companies are expected to fall by 0.7 percent in the third quarter, according to Thomson Reuters data.
* Wall Street closed higher on Monday as energy shares benefited from a surge in oil prices and as Apple jumped due to rival Samsung Electronics' worsening smartphone recall crisis.
* The iPhone maker's stock was up 1.25 percent in premarket trading on Tuesday.
* The markets are likely to be volatile as the earnings season will turn the spotlight on valuations, while a tight race for the White House and a potential U.S. interest rate increase by the year-end will add to the jitters.
* The dollar rose 0.53 percent, marking the second straight day of gains as investors price in higher expectations of a rate hike in December.
* Minneapolis Federal Reserve President Neel Kashkari is scheduled to speak at 11:00 a.m. ET (1500 GMT).
* No major economic data is expected on Tuesday.
* Shares of Illumina plunged 26 percent to $136.25 after the diagnostic test maker cut third-quarter revenue forecast for the second time in a row.
* JinkoSolar rose 4.2 percent after the solar cell maker entered into an agreement for the sale of its Jinko Power downstream business in China.
* Caterpillar rose 1.3 percent to $89.35 after Goldman Sachs and Jefferies raised price target on the stock.
Futures snapshot at 7:05 a.m. ET:
* Dow e-minis were down 14 points, or 0.08 percent, with 17,670 contracts changing hands.
* S&P 500 e-minis were down 3.25 points, or 0.15 percent, with 112,451 contracts traded.
* Nasdaq 100 e-minis were down 3.25 points, or 0.07 percent, on volume of 16,440 contracts. (Reporting by Yashaswini Swamynathan in Bengaluru)