Never a good idea to trade away a player for lower value than what you drafted him at if at all possible. I'd wait and see if Dayne really has much of an impact on Tiki's playing time. The way I see it, Tiki's value doesn't sound like it could go much lower in your league, but it could definitely go up. I don't see you losing much more value with him, but you could sure gain some!
That's my two cents and it's worth every penny of it!