Neil Warnock has said that he would have been "staying for the wrong reasons" if he had remained at Rotherham United.
Warnock secured the club's Championship status after three months in charge but opted to leave on Wednesday.
Speaking to BBC Radio Sheffield, the 67-year-old admitted he nearly signed a new contract last week.
"I did feel the club needs somebody to commit themselves now to actually take it forward," he said.
"The chairman has a dream of the Premiership, and quite rightly so, but I do think that's a few years away yet.
"The main thing is consolidating in the Championship, have a steady season where they're not flirting with relegation and get the infrastructure correct for when they could make a push."
Warnock presided over 16 matches at Rotherham, taking them on an 11-game unbeaten streak that moved them out of the relegation zone.
Rotherham had been confident of keeping Warnock at the New York Stadium, but Warnock felt that the club needs a manager willing to commit to a long-term run.
"Ten years ago, I think I would have signed a three or four-year contract with the chairman because I trust him that much," he said.
"With one or two key signings Rotherham have the nucleus to take the club and try and be in a comfortable position."
Warnock has managed at 14 clubs in a 36-year career, including stints at Leeds United, Queens Park Rangers and Huddersfield Town.
"The club now is in a situation where it needs somebody to come in for a couple of years," Warnock added.
"I have that one season left in me and I felt at the end, I would have been staying at Rotherham for the wrong reasons."