The subordinate clause, "whenever he has time", is an example of a noun clause. A noun clause is a type of subordinate clause that is introduced by words such as who, whom, whomever, whenever, when, how, whether, which, why, where, whatever and what. A noun clause functions as a noun and can also function as a subject, direct object, object of a preposition, predicate nominative and indirect object.
The Answer would be the sentence "It suddenly looked huge and intimidating as it spread out before me" because it is giving you an image reflecting how nervous the person is when he gets on the field.
