Goaltenders get injured all the time, but in-game injuries that occur are not always their fault.
More likely, it is due to a player crashing into them when they're not expecting it.
Take the Craig Anderson injury, for example.
If there had been a "stop line" of sorts—say, another crease that offensive players had to stop at on odd-man rushes or else they'd get a penalty for "attempting to injure" if they make contact with a goalie—there would likely be a reduction in goalie injuries.
Recently, goaltender interference was addressed by the NHL's Department of Player Safety.
Unfortunately, all of the references used by the Department of Player Safety showed plays where the interference was as a result of a player driving to the net while in possession on the puck.
The plays that could result in the most injury to a goaltender are those where the goaltender does not see a collision coming.
They are plays like the Kreider-on-Anderson collision, where the attacking player does not have the puck and the puck is not coming his direction.
These are the kinds of plays to which the "stop line" is meant to apply.
The fundamental problem is the fact that players are allowed to drive the net for the sake of getting a stick on the puck. This results in a higher number of collisions that wouldn't otherwise be happening if a player had to attempt to stop before reaching a goaltender.