Complex sentence: Team members with a prosocial orientation are considered more valuable team members by their peers, due to their tendency to assist others on their own volition, instead of waiting until their assistance was absolutely necessary or instructed by a superior.
Split into simpler sentences: Team members with a prosocial orientation are often considered more valuable team members by their peers. This is due to these prosocial members tendency to assist others on their own volition, instead of waiting until their assistance was absolutely necessary or instructed by a superior.