But, today, the 27-year-old revealed he's returned to his roots purely and simply in a bid to put an injury-ravaged year behind him as he seeks to get his career back on track with English Premier League outfit Birmingham City.
O'Connor hasn't kicked a ball in anger since last October and now has to prove his fitness to Blues boss Alex McLeish to trigger a contract extension at St Andrew's.
The Scotland striker has been working under the supervision of ex-Hibs fitness coach Dougie Fowler and, he insisted, he'll be returning to the Midlands for the start of pre-season training in the best shape he's been in for years.
In an exclusive interview with the Evening News, he said: "I've been really depressed at how little football I've been playing. I've had five operations over the last two years around my groin and hip areas but now I am absolutely flying.
"I reckon I'm now in the best shape in the last five years, my sharpness is back as is my strength and I'm feeling really positive.
"I have a two-year contract extension at Birmingham but that's been put on hold because I have to prove my fitness to the club.
"I asked for six months, although Birmingham wanted to offer me longer and, if everything is all right, then the two-year deal can be signed."
Having moved to Birmingham following a spell with Lokomotiv Moscow, O'Connor insisted the Blues' support have only had glimpses of the best of him, scoring in every pre-season game two years ago and again at the start of last season.
His appearances, however, have been sporadic thanks to the injury problems which, it is felt, could well be down to playing and training on artificial surfaces in Russia.
He said: "We'd train on them every day and play on them at least twice a week, twisting and turning and in the cold. That's what Alex McLeish puts it down to."
For someone who scored 58 goals in 136 starts for Hibs, form which earned him a Scotland cap at the age of 18, it's easy to understand O'Connor's frustration at the way the last couple of seasons have gone, limited to barely 50 matches for his current club. And, likewise, his Scotland career has been put on hold, the last of his 15 caps coming in the 1-0 defeat by Holland at Hampden last September. O'Connor, however, is just as keen to impress Scotland boss Craig Levein as he is McLeish, following a somewhat chequered international history.
He said: "Craig came down to speak to Barry Ferguson, James McFadden and myself and he seemed keen to get me back into the Scotland set-up. First of all, I have to get my fitness right, get into the Birmingham side and score a few goals.
"But getting a call from Scotland is most definitely an ambition and if I can play to my full potential then I am sure that will happen.
"However, we have a lot of good strikers at the moment. Kenny Miller is probably the most experienced but Kris Boyd is back in the international fold, Steven Fletcher did really well in his first season in England, Kevin Kyle will have ambitions now he is with Hearts and Lee Miller will also be keen to continue to be involved.
"And don't forget my old pal Derek Riordan. He's still banging in the goals for Hibs and I'd imagine he'll also get a sniff."
Birmingham surprised many by finishing last season ninth on their return to England's top flight and, O'Connor insisted, he'd be happy with a similar outcome to the forthcoming campaign. He said: "Birmingham did well but the gaffer said the one thing that was missing was a striker to put the ball in the back of the net.
"We could have done better but I think we'd be happy to be mid-table again.
"The gaffer keeps going on about 'second season syndrome,' pointing out the number of teams who do well in their first season but then struggle so to do what we did last season would be great."
Having worked so hard on his fitness over the past few weeks, O'Connor is convinced he'll be able to persuade McLeish to give him the opportunity to help Birmingham achieve that ambition.
He said: "Two summers ago, I worked with Dougie and I went back to score in every pre-season game and then got something like five in eight in the league before I was injured again.
"I was really flying then, feeling very strong and was running away from the others in training but I'd say I'm now ten per cent fitter than then so I'm sure the boys at Birmingham will see a difference.
"I'm out twice a day with Dougie, a lot of stuff on Arthur's Seat and then an hour or 90 minutes in the gym.
"Dougie and I just seemed to click when we were at Hibs, he has that ability to get the best out of me, to get me to a level without breaking me, he's absolutely fantastic at what he does." O'Connor is well aware being spotted on a regular basis as he hones himself towards peak fitness has set the rumour mill running but, he insisted, that while he'd one day love a return to Hibs, that day isn't quite yet.
He said: "It's a question I've been asked a few times.
"Hibs will always have a special place in my heart, the fans have always been terrific to me and I still have the ambition to come back to the SPL and play for Hibs again, I have unfinished business in England. I'm not trying to be disrespectful to Hibs, I'd never be that to the club or the people at Easter Road, but I think everyone would agree that every player wants to test himself against the best.
"England certainly has that, look at the World Cup and every country seems to have one, two, three or even four players from the Premier League.
"As a striker you are playing against defenders who cost 20 million which gives you that extra wee buzz when you do score against them. Then you are going to places like Old Trafford, the Emirates, Stamford Bridge and so on, places where the atmosphere is fantastic."
The return of West Bromwich Albion to the top echelon will also mean a plethora of derbies for O'Connor and his team-mates with Aston Villa and Wolves, complete with former Easter Road team-mate Fletcher, all to be played.
O'Connor said: "I think I'd probably look to the Wolves one more than the others, Christophe Berra trying to stop us scoring while Fletch will be looking to get one at the other end.
"Christophe has done well since he came south from Hearts while you could see from early on at Easter Road that Fletch had all the attributes to be a top striker.
"I watched him last season and he did very well.
"I know people will look at the 6.5m Wolves paid, but down there that's pennies to a lot of clubs.
"I'll look forward to the derbies but, to me, nothing will match the games with Hearts, particularly scoring at Tynecastle.
"Luckily enough for me, I managed to win a few derbies and score in a few and that picture of Dean Shiels and myself sitting on the pitch over there having each scored is one I'll never forget."