Former Aston Villa boss Graham Taylor is convinced that Martin O'Neill quit the club because of a dispute over transfer policy.
Villa confirmed O'Neill had resigned with immediate effect on Monday, with no official explanation being given as to the reason for the Northern Irishman's departure.
It has been speculated that O'Neill had not been given assurances that all the money gained from the expected sale of star midfielder James Milner to Manchester City would be available to reinvest in new players, while there is also a suggestion that another prized asset - Ashley Young - is a target for Tottenham.
Former England boss Taylor, who managed Villa from 1987 to 1990, believes the club's transfer policy will have been a key factor in O'Neill's exit.
"I'm not totally surprised, I think it's been coming," Taylor told BBC Radio Five Live.
"What has happened - and although some of it is guesswork - is that he realises he will need more money to take this club further and it would appear that is not forthcoming and that he would have to sell in order to purchase.
"I think Martin has said 'hold on a minute, that's not what we're looking for, that's not why I came to this club' and he has decided to walk.''
Asked whether finishing sixth was now the best Villa could hope for, Taylor said: "It could be and it's very sad if it does turn out that way. Martin took over and year by year the club has improved.
"It's been hard work and it goes without saying how hard it is to break into that top four and one of the things you need in this day and age is the money to do it.''
Taylor sees Monday's news as another example of the receding power of managers, with owners exerting ever greater influence over transfer policy.
"In the Premier League there are more and more people now who should be named head coach and not managers, the people who are running these clubs are very wealthy people and it is they who want the final say,'' he said.
"More and more managers are responsible for the first team but not for all football matters, we're following the continent in that respect. Martin was one of those people who was responsible for everything on the football side.''
Taylor is worried what effect O'Neill's exit will have on Villa, who have improved steadily under the former Celtic and Leicester manager.
"Villa were on the way, they were slowly getting into it and it is a shame that this has happened,'' Taylor said. "Martin's reign has been very successful at Villa.''