However, the Celtic manager was determined to have a clear-out and has already stated he plans to make 10 new signings.
It was against that backdrop that Caldwell opted for the lure of the Premier League with Wigan, snubbing a move to the Championship to join former Celtic boss Gordon Strachan at Middlesbrough.
"A contract was in the offing and, as happens many times, one party wants one thing and one wants the other and you can't come to an agreement," said Caldwell, who has signed a four-and-a-half-year deal with Wigan, of his parting with Celtic.
"I think I had opinions of what I was worth to the club and they had different opinions.
"That happens in football. I don't think they will have any regrets and hopefully I won't either.
"In the end it was time for me to move on. It (his decision to leave) was a while ago but for a long time the writing has been on the wall.
"I have nothing against the club, I thank everyone at the club for all they have done for me over the years.
"I did my very best for them right up until the last day I was there and I think that is all you can ask.
"I would have stayed until the end of the season as I was more than willing to help the club try to win the league again but Gordon and (Wigan boss) Roberto (Martinez) came in and they allowed me to speak to them."
The Scotland centre-back, whose brother Steven plays his football not too far away in Burnley, refused to openly criticise Mowbray.
However, he made a point of stressing how impressed he had been by the persistence of Wigan manager Martinez in his pursuit - especially as he had almost decided to decamp to Teesside.
"When you get older you appreciate that when managers want you they show it and I think Roberto has done that," added last season's SPL Player of the Year and Scottish Football Writers Footballer of the Year.
"I worked with Tony at Hibs and for six months at Celtic. But he has to get his own team and style of play and he will have to get people out and bring people in to do that.
"In football at times you have to move on and get a different challenge because you can become stale if you are in the same place for too long.
"It was crazy at the start of the week. Gordon Strachan, the manager at Middlesbrough, was a big pull there as I had a great relationship with him.
"But Roberto spoke to me a lot and convinced me to come to Wigan and challenge myself in the Premier League.
"He had a lot of information on me that even I didn't know about. It is good to feel wanted and he really made me feel wanted here.
"It was pretty last-minute and I think that was down to the manager here who was very persistent and in the end I just had to come here because he didn't give up.
"He told me he had a big plans and that really excited me and I'm looking forward to it."
Martinez believes Caldwell has all the attributes to be a real success in the Premier League.
"I am certain that he will see in the next six months that he has made the right move and his career will kick on to the next level," said the Wigan boss