Injury Keep/Substitute choice doesn't make a difference

Franchise mode. My starting LT goes out with an injury, a play or two later I'm presented with the explanation of the injury and asked whether I want to keep or substitute the player. I choose substitute, and in my mind this means the starting LT should be on the bench the rest of the game. A few plays later, I realize the my starter is in the game when he sustains a season ending injury.

If I choose to substitute a player when given the choice, that player should stay out for the rest of the game. Otherwise what is the point of even presenting us with the option?