I'm always "all in" with new players. It's mainly because if I've purchased them, it was because I had a hole to fill and my rule is that I don't buy unless the new player is at least 1* higher. I've been disappointed only once but even that guy is still on my roster since he fill 2 holes as a sub (DC and DR), and he seems to have decent form coming off the bench.
Anyway, in my opinion, if you didn't buy him to start, and there's no need for him to start, why did you bother at all? Seems like a waste of money.