Good question. I should probably make this clearer on the site.
The short answer is that if a player is injured we won't put them into your lineup unless there's an open spot (ie. we'll never bench a healthy player for an injured one).
Long-winded: we build thousands of simulations of every NBA game based on teams' recent lineups and depth charts, and incorporate current injury data into these. This lets us do some really cool stuff, such as bump up the minutes projection (and thus the value) of guys who are next in line on the depth chart at the position of the injured player. We then optimize your lineups over these simulations to maximize the chance that you'll win your matchup.
The short answer is that if a player is injured we won't put them into your lineup unless there's an open spot (ie. we'll never bench a healthy player for an injured one).
Long-winded: we build thousands of simulations of every NBA game based on teams' recent lineups and depth charts, and incorporate current injury data into these. This lets us do some really cool stuff, such as bump up the minutes projection (and thus the value) of guys who are next in line on the depth chart at the position of the injured player. We then optimize your lineups over these simulations to maximize the chance that you'll win your matchup.