1) Certainly in RT leagues where PA are not totally predictable. (And the board is dominated by TRADs at the moment due to drafting schedules.

2) INNs are like minor leaguers. When a MLB club has nobody to play a position, they bring someone up. They are replacement level players.

3) Anybody who take on a project team, especially mid-year, knows that you cannot immediately fill all the positions.

4) Definion if innocuous: "producing no injury : HARMLESS"