Assistant(e) makes sense, but I have in mind a particular Little League baseball team we were associated with once. For many teams the coach does the managing functions too, but in this one, coach and manager were distinct and separate roles. The coach taught the players how to throw, catch, and bat, decided who would pitch, etc. The manager kept track of the schedule, contacted the players in case of a rain cancellation, coordinated parent volunteers, and so forth. A water boy, for example, would have far less responsibility than that. Edit: just saw Keumar's intendant, which isn't one I've seen often - I'll have to look at that more closely.