The phrase "an early exercise" is correct and usable in written English.
It can be used when referring to a task or activity that is done at the beginning of a process or period.
Example: "To warm up, we will start with an early exercise that focuses on basic techniques."
Alternatives: "a preliminary task" or "an initial activity."
It was an early exercise in power plays.
I suppose it was an early exercise in developing the imagination.
Although not original, his inclusion of Reconstruction as an early exercise in nation-building is important.
Unabashed, Stead published "The truth about the navy", an early exercise in "investigative journalism" which claimed - without much supporting evidence - that Britain was vulnerable from attack by sea.
In black and white, Ms. Rosmarin painted the fuzzy gray "snow" of blank television screens, an early exercise in replicating random patterns in the everyday environment.
William Faulkner typed the story on the back of University of Mississippi letterhead, an early exercise in fiction writing about a fur trapper's trip to a big city.
A few even received permission to change the exercise price on their stock options or to use an accounting maneuver to cancel an earlier exercise of options that, in hindsight, looked financially foolish.
Moreover, the pope's reluctance was increased by the fact that he was being asked to declare illegal an earlier exercise of papal power which had licensed Henry's marriage to his brother's widow of a kind that brought a good deal of money to the papal coffers.
Judging by Army materials VICE News reviewed, Dragon Spear was adapted from an earlier exercise initially planned in response to events in the Republic of Georgia in 2008, when the country was being partially annexed and quasi-invaded by Russia.
"It will be an important early exercise between the United States and China, early in the term of Xi Jinping and early in the second term of President Obama".
