Previous research has found that verb argument structure characteristics (such as the number of participant roles in the situation described by the verb) can facilitate or hinder aphasic language production and comprehension in constrained laboratory tasks. This research needs to be complemented by studies of narrative or unrestricted speech, which can capture the spontaneous selection of verbs and grammatical structures by people with aphasia and may be particularly sensitive to the relative cost of access to different verb types in more natural conditions. Focusing on the number of subcategorization options, we investigated verb argument structure effects in a large sample of narratives from AphasiaBank, by speakers with aphasia, as well as control speakers without brain damage. Verb argument structure complexity did not negatively affect verb selection in any type of aphasia. However, people with aphasia, particularly with Broca's aphasia, used verbs in less complex and diverse ways, with fewer arguments and less diverse subcategorization options. In line with previous research, this suggests that deficits in verb use in aphasia are likely due to difficulties with the online application of or partial damage to verb argument structure knowledge.