After his contact expired with Glasgow Celtic, O'Dea — having had loans stints with Reading, Ipswich Town and Leeds United — had expected to stay in England. He was mulling over options while he recovered from a disappointing Euro 2012 with Ireland, in the wake of 18 months of qualifying.
It was a process that ultimately led him to Toronto FC, but not before he had done a lot of soul-searching.
It started when his agent asked him if he would consider playing in Ukraine — in the words of O'Dea — "for big, big money."
"As a footballer, when I was younger, you say you want to play for football. But money starts to come into it when you have a family. And you only have a short career," O'Dea added.
He started to thinking about the Ukraine offer. And his agent started showing him other foreign possibilities, including Italy and Germany.
The MLS was also an option. O'Dea (pronounced O'Dee) says he was "50-50" on it, but agreed to come over and take a look.
He saw Toronto's training facility, watched a game "and I was really sucked in by it, to be honest with you.
"I think that was the big point in my career that I thought 'Do I want to be a footballer or do I want to be rich basically?'" O'Dea told The Canadian Press. "Obviously you earn good money in football and I wanted to be a footballer, I wanted to be remembered. I think here (in Toronto), I look at the club, the infrastructure, there's not many clubs that will beat the training facility, the way you travel, the way you stay, the pre-season. Everything you're given is a good as you can get.
"But one thing that really appealed, it sounds strange, there's no history at this club. So everything you do good will become history and you'll get remembered. And that was the decision I made — was it to make money or to be remembered as a player ... And that really appealed to me — making history.
"I came from a club at Celtic where you're constantly talking about history. Here the club is so young, it hasn't achieved anything yet. Hopefully you're going to be the first to do it."
Toronto FC is a blank sheet, indeed. In six seasons to date, it has never made the playoffs. What little history it has is bad.
O'Dea joined a club suffering through a franchise-worst season and has yet to take part in a regular-season win. Still he says he has no regrets about his career choice.
"I think anyone who knows me, family and friends, (know) I can be quite mouthy on the pitch but I think things through quite a bit. I might come across as a guy of impulse but I'm not."
O'Dea, who turned 26 on Monday, signed with Toronto on Aug. 3, playing just nine games in a season cut further short by a thigh injury.
The centre back had been off for some six weeks after Euro 2012. He was unfit but Toronto needed defensive help, so he was thrown in.
"It might sound strange but I was actually match fit, but I had no base of fitness so I was recovering very slowly after games. I wasn't feeling great at times. As I happened, I pulled a muscle because of it. So I never felt great last season at all."
O'Dea, however, sees some positives. He got a taste of the league and opposing players.
Plus he has a home, after spending his time last season in Toronto in a hotel. After camp, he gets the keys to his new apartment and wife Melissa and daughter Lucia join him three days later.
"Everything settled now," he said.
"All my attention's on football," he added. "That's the way it should be."
This off-season was a luxury, almost three months off after being used to four weeks off. After seeing limited action due to injury, he was eager to resume training.
After taking 10 days off to rest his body, he started work with Motherwell and spent eight weeks training there. He took a week off at Christmas and then resumed practising.
"I came back in probably in the best shape I've been in in a few years really because I've not had that much training," he said. "I feel good now."
Training in the off-season at Scotland's Motherwell has reinforced Toronto's pluses.
O'Dea, while extremely complimentary about the Motherwell players there ("proper pros"), recalls how the facilities would be freezing when you arrived. Breakfast was a bowl of cereal "at best."
"Here you're given everything."
O'Dea has enjoyed Toronto, after living in the fishbowl that is life as a Glasgow Celtic player.
"Glasgow, until you've played there, you don't know how intense it can be. You go out for a meal at night with your wife, you could be getting shouted at going into a restaurant. Everyone knows you in Glasgow and everyone's looking at you. But you don't know whether the person looking at you loves you because you're Celtic or hates you because they're Rangers. It's an intense city."
O'Dea got used to it, having moved there when he was 15.
"I learned how to deal with it," he said. "I loved it, I did like the intensity."
O'Dea found himself in the tabloids a few times.
The Sun raved about his then-girlfriend Melissa, calling her a simmering beauty who is one of five "equally gorgeous" sisters. The Daily Record reported that a "drugs baron" threatened to gun down the defender in a nightclub over claims he had talked to the gangster's girlfriend.
He says he loves Toronto — "a fantastic city with lovely people." And he loves being out of the spotlight.
"I've had a few people come up to me, but only to say hello," he said of Toronto
But Glasgow will always be home to O'Dea and his wife, also a Glaswegian. He has a house there and will move back when his playing career is over. A career in coaching may be in the cards; O'Dea wants to start taking his coaching badges.
Older beyond his years thanks to his young start in the sport, O'Dea is realistic about football as a career and is grateful for his good fortune.
He moved over from Ireland at the age of 15-16 with four others from the same club. One is playing in Northern Ireland, he's not sure what happened to the other two.
He knows he is lucky he made the grade, since education was sacrificed for his sport. He also know that those who went the U.S. college route, face an uphill task coming into pro leagues at 24.
On an MLS salary of US$436,250 in 2012, O'Dea knows how fortunate he is. But he also knows football.
"I don't expect anyone pat me on the back for the salary I'm on because I know compared to the league, that's a very good salary," he said. "But believe me I could have earned three times that in other places — I still could. But as I said what do you want to be? Do you want to be a footballer or do you want to be a multimillionaire.
"Hopefully you can be both, there's a lot of people who are both. But I'm not. I want to be. But I want to earn money because I've been successful. And I've been lucky. At Celtic I was successful and I got rewards for that.
"People only mention money when you're not doing well, because they want value for money. Hopefully come the end of the season, people don't look at our salary, they just look at a good team.
The Dublin native, who supported Celtic as a boy, was just 16 when he found himself playing against men in the Celtic reserves.
He made his first-team debut at 18 before 60,000. Four games in, he was at the San Siro in Milan in front of 90,000 in the last 16 of the Champions League.
"I could have sank but I managed to stay afloat, if you like," he said. "I've learned and grown up with pressure and that's living in Glasgow and it's been brilliant for me. I learned how to be tough and it stood me in good stead."
"That's one of the biggest things I learned was you need to be a tough character in football," he added. "Especially in this league (MLS). This is the worst league I've come across for players. Players have no rights, nothing's in their hands, you can be traded, so you need to be tough. I think the players that make it in this league are probably very tough."
He was 20-21, when Tony Mowbray made him Celtic captain.
He signed a 3.5-year deal with Celtic, going out on loan to Reading for a few months to gain more experience.
Neil Lennon came in as manager and O'Dea was told the next year he could go out on loan today. It was not what he wanted to hear.
"In hindsight I should probably have said 'No, I'll stay and I'll fight (for my job).' But being the type of character I am, I thought I wanted to play all the time. I should have maybe been a little more patient."
He enjoyed his season at Ipswich but when he came back, Lennon had signed 15 new players.
"The squad needed a change ... and he's done brilliantly there so I can't really argue with anything he did."
In all, he played 70 games for Celtic and scored in the 2-0 League Cup final win over rival Rangers in 2009.
O'Dea went out on loan to Leeds. Clubs were interested in him but, with his contract due to expire, weren't willing to pay to get him.
And so started his journey to Toronto.
Celtic, however, will always have a special place for O'Dea — he wears No. 48 in honour of mentor and Celtic legend Tommy Burns — although his emotion for the club is tinged with realism.
"I loved it. It could have been different if I maybe stayed but it's neither here not there. It doesn't mean anything now."