Delph was man of the match in Villa's 3-1 home victory over Blackburn as he completed back-to-back 90 minutes for the first time since he arrived at the club two years ago.
Having just turned 18, splashing out ?6million was seen as a gamble at the time for a teenager who had only one Championship appearance on his CV, never mind having played in the Premier League.
Delph's debut campaign was hit and miss before suffering a cruciate ligament injury towards the end that sidelined him for eight months and restricted him to just eight appearances last season.
Despite his issues, Delph signed a new five-year contract in March that ties him to the club until 2015, thanks to owner and chairman Randy Lerner.
The arrival of McLeish as manager in June, in particular, has also proved revelatory as a new training regime tailored for Delph has so far aided his fitness, and crucially his breakthrough.
"After sitting down and speaking with the manager, he's confident in me and I'm very happy with him," said Delph.
"The gaffer has been unbelievable. We've limited my training and focused on building muscle in other areas of my body.
"It seems to be working. I don't seem to be losing fitness, so it's great management from him.
"He's an experienced manager, and if he says I have to do something different for a few months or forever, then as long as I stay fit, I am happy."
As far as Delph is concerned he has "a lot of lost time" to make up for, and a list of people to whom he is grateful for resurrecting his career.
"I can honestly say I've come out a stronger person," added Delph, who started out at Leeds at the age of 17.
"I've no one to thank but those around me, my family and especially people like (physios) Alan Smith and Stuart Walker, and the doctors here now, and those who have gone.
"The physios kept me going. I'm not the easiest person to work with when I am angry and frustrated.
"It was hard to keep my mouth shut at times, but everybody is entitled to have a little moan.
"I've a lot of respect for the people I work with, and I do as I'm told. They told me to shut my mouth and get on with it.
"Alan Smith took a lot of grief, but he's an unbelievable physio. He's worked with players with injuries far worse than mine.
"As far as he was concerned I was a little guy with a big gob who he put into place quite quickly."
Delph is now naturally determined to stay fit and assist Villa with their push under McLeish this season, but he also knows he owes a few people as well.
"As far as I see it my injuries are behind me now, and my focus is to push on in my career and do well for the manager and chairman, as they have for me," said Delph.
"The chairman put a lot of faith in me by giving me a new contract, speaking to me, looking after me on that side of things.
"For me to repay them would be the best thing I could do."
Should Delph stay healthy, McLeish believes the 20-year-old would be like a new signing, so saving him a lot of money.
"Fabian has so far - touch wood - started really well. He is very decent and looks gifted on the ball," said McLeish.
"He got his tackles in, his positional sense was terrific, and hopefully he will get better and better, and we will manage his training throughout the season.
"I've told him if we could get somebody like him making a breakthrough it could save us having to spend a fortune."
Goals from Gabriel Agbonlahor and Emile Heskey put Villa 2-0 up over Rovers inside 25 minutes, and although Morten Gamst Pedersen pulled one back early in the second half, Darren Bent secured three points.
The result leaves manager Steve Kean's side bottom of the table after two games without a point.
Source: Team Talk
Source: Team Talk