Martin O'Neill not only plans to do all he can to keep him as his assistant with the Republic of Ireland national team, but the former Hoops boss also revealed the 42-year-old is considering other job offers.
O'Neill confirmed Celtic's major shareholder, Dermot Desmond, sought and was given permission to open talks with Keane over the position vacated by Neil Lennon last week.
However, O'Neill also revealed the former Sunderland and Ipswich boss is not the only man currently under consideration. It is understood Owen Coyle remains in the frame, while Malky Mackay, Michael Laudrup and Stevie Clarke are also hoping to get a call.
So, although the bookies have hammered the odds about Keane getting the job all the way down to 10-1 ON, O'Neill believes it is not the foregone conclusion this might indicate. He explained that, initially, he had been sure Henrik Larsson was going to get the job because of the money being wagered on the former Hoops striker.
O'Neill said: "I've had chats with him (Keane). I will speak to him again and he'll keep me in the loop the whole way through.
"I obviously want him to stay here for every reason under the sun. I think he will be great. He has a number of things to think about, including a number of other offers as well. I will be really disappointed [if he goes]."
That was no barrier to O'Neill granting Desmond permission to speak to Keane, although he did explain when he got the call he thought it was just to ask his opinion of him.
He said: "Naturally, I just thought he was asking in a more general way about Roy's managerial qualities. I've often said he will be a manager again himself. I just didn't expect it that quickly. It was only an informal conversation he (Desmond) was having. I don't know the ins and outs.
"I think they do have a list of people they are speaking to. You never know, maybe they might speak to someone else."
O'Neill has been working with Keane since February and has seen him grow in the role. He said: "He genuinely loves it here. I hate to use the word rehabilitation, but it has been really great for him. He has enjoyed the role."
O'Neill can see what a step up Celtic could be, but countered: "When I say I'll do my best to keep him, you are right when you say these opportunities are there. But, by the same token, obviously I re-emphasise how much he is wanted here and what he has brought to the party.
"Eventually it will be Roy's decision. My advice? I want him to stay."
Keane is scheduled to travel with the Republic to London today for tomorrow's game against Italy at Craven Cottage, then on to America for a match against Honduras a week today.
O'Neill admitted he did not know if more talks with Celtic are planned before then.
He was more definite about the possibility of Keane remaining as a part-time assistant to him as well as managing Celtic.
O'Neill confirmed this has not been discussed, adding: "Roy has also been talked about as an assistant manager at club level. I think that is something he might have thought about and doing the job with us.
"If you are a full-time manager at a club, I don't know whether it would work. [But] if there was a way of keeping him here, I'd like to try and look at that as well."
O'Neill managed Lennon at Leicester then at Celtic, and had been an important ally while the rookie was finding his feet as the Hoops boss.
He said of Lennon: "I signed him twice and he was fantastic. He has gone on, but I'm sure there were moments way back where he thought management wasn't for him.
"Things went brilliantly for them [Celtic], but he has had to work hard. The Champions League run the season before last was phenomenal. You get great highs from that
"Roy, as a manager, I think did great at Sunderland, and was very disappointed with things at Ipswich.
"There are a few similarities and a few contrasts [between them], but, essentially, they are both managerial material."