Birmingham-born Ward, 23 tomorrow, joined the Bramall Lane side in a £330,000 switch from Chesterfield four months ago.
And he revealed: "It was after I had recovered from the road accident that O'Leary told me I could leave Aston Villa because I was not going to make the grade there.
"I had been out of the game for four months, recovering from the car smash which left me with a fractured and dislocated elbow, a broken nose and a badly gashed knee.
"I was driving home from training when I lost control of the car and hit a tree.
"The ambulance crew who rescued me said I was lucky to be alive.
"But I was determined to rebuild my career when O'Leary, who was manager at Villa Park at the time, called me into his office and advised me not to sign a new one-year deal the club had offered me as I did not figure in his plans.
"He was bang out of order for doing that and I signed the contract anyway.
"But not long after I was on my way to Torquay and then, six months later, to Chesterfield."
All that was three years ago but now, after a dramatic up-turn in his form and fortunes at Saltergate, he stands on the brink of the big-time.
Ward snapped: "There is no way I was going to let one man's opinion stop me from doing what I wanted to do.
"I was determined to prove O'Leary wrong by showing I can cut it in the Premier League and I am confident I can do that with Sheffield United. I have worked my nuts off to get where I am now and I am proud of how far I have come in such a short space of time since leaving Villa.
"It has been one hell of a ride - and now I could be just 180 minutes away from realising my dream of being a Premier League player.
"I am a highly-motivated person and it has always been my ambition to keep progressing and work my way up to where I am now."