"I've been out of the country for four days and must admit you've caught me by surprise on this one, I didn't know anything about it," Blackwell confirmed.
"I can't comment on it and won't comment further until I'm back in Leeds and that's all I can tell you."
But Worthington, a former Leeds full-back, says in the Eastern Daily Press: "Rob is a player we have enquired about. We would like to try to bring him to the club, but we have to wait and see at the moment.
"Linking him with Rob Earnshaw would be a nice pairing if we could make it happen. We have made an enquiry to Leeds and that is where we are at, we don't know whether Leeds will let him go."
And Leeds chief executive officer Shaun Harvey said: "We have been aware of Norwich's interest for some time.
"Any Championship club would be interested in a player of Rob's ability but as ever we will make decisions that are in the best interests of the club."