If he was coming to another buck then I would use the horns. He may just be territorial and not horny yet? I would put him up and stink him up with some young buck scent, wait till you usually see him and give some young buck grunts and wait fot the magic to happen. Good luck to you.
(as a side note I have never used a decoy deer, just repeating an article i just read yestarday. I am going to use one next week though!)