Sidelined by an injury.
The political sidelines.
- Either of two lines marking the side limits of a playing area, as in football or tennis.
- The areas just outside these lines.
- A line, as of merchandise or work, in addition to one's main line.
The coach stood on the sidelines and bellowed commands at the team.
The coach sidelined the player until he regained his strength.
- In the area along the sidelines.
- Outside the main sphere of action.
- Not actively participating.