The answer to your question would be that the clause underlined is a noun clause. A noun clause, also known as nominal clause, is a group of words acting together as a noun. In addition to this, these clauses are always dependent clauses since they do not form a complete sentence and therefore cannot stand on their own as a complete thought. Just as nouns, they can function as subject and object of a verb, subject complement, object of a preposition, and adjective complement.
Coach William's intent is [that all players will have a chance to hit the field]
In this case, the nominal clause has been introduced by the complementizer "that" and it functions as a subject complement. A subject complement modifies, describes, or completes the subject of a clause. You can see this by asking the following question: What was Coach William's intent? Answer: that all the players will have a chance to hit the field.
