Firstly I do not believe for one minute that the manager signed Murphy for the future, he was signed expecting to make an immediate difference and you don't spend your transfer budget on players for the future when you are in a position we find ourselves in, neither do you purchase them when you have an abundance of players already playing in that position.
Murphy is 24 I would not say he is one for the future, he should be reaching his best years now, if he was any good we would then have at least 6 years out of him.
When you say an investment then that has already failed as Murphy will not be worth the money we paid for him, he must have already decreased in value.