Parker said: "I'm bang on schedule from what I can gather, but I haven't put a time on it. I'd like to think if I'm back around Christmas I will be happy, but it might take longer than that, so mentally I'm prepared for anything."
Parker has been determined not to be seen moping around Thorp Arch during his rehabilitation.
He added: "I've seen some people who've been injured for a while who don't want to talk to you because they are in such a bad mood.
"I've not been like that. If I have a smile on my face I hope it will rub off on other people. I'm not a doom and gloom person."