Now the 35-year-old central defender doesn't want the journey to end — and with good reason.
Three straight victories, including a massive 1-0 road win over the Seattle Sounders last week, has the Whitecaps in control their own destiny as they push for a playoff spot.
Four points in their final two regular-season games — beginning with Saturday's road matchup against the lowly San Jose Earthquakes — would guarantee Vancouver a post-season berth for the second time in three years, while anything less over the final two weeks puts other results in play.
It's a startling turnaround for a team that was left for dead just a few weeks ago, and one that O'Brien partly credits to a candid players' meeting last month.
"I think the penny's dropped. I think we understand the importance of the time of the year," he said before departing for San Jose. "It was mentioned that not everybody's going to be here next year and we've got a real opportunity to make a statement to do something together. I think we're determined to continue what we've got for as long as possible."
With more than 300 games in the English Premier League under his belt, O'Brien joined the Whitecaps midway through the 2012 campaign. In 2014, he has been instrumental in calming a defence that lost captain Jay DeMerit to retirement in July and has had to offset a lack of goals at the other end of the pitch.
But even O'Brien — who sat out seven straight games from June 28 to July 30 because of injury and coaching decisions — didn't expect to enjoy his tenure in Major League Soccer this much.
"I think in 2011 — these were only private thoughts — I was close to packing it in. When I say pack it in, stop playing football," said O'Brien, who was born in England but played 26 times for Ireland at the international level. "It taught me that even though you can go through a rough period, if you can keep digging away there's light at the end of the tunnel.
"I've certainly enjoyed my time here. I think physically I'm as fit as I've ever been. Mentally, I'm really enjoying coming into work every day."
The players have talked a lot about the spirit in the squad, and O'Brien said the additions of Pedro Morales, Matias Laba and Sebastian Fernandez — among others — have been instrumental in creating a unique camaraderie.
"The South American boys that we've brought in are the life and soul of the dressing room — they keep chanting my name for some reason," O'Brien said with a laugh. "I don't know why that is, but I've found it a real nice experience and one that I'll learn from.
"I think it is a special dressing room. It's certainly one that I've enjoyed being a part of this year, and long may it continue."
The next critical step in that process comes Saturday when Vancouver (11-8-13) will try to avoid a letdown against San Jose (6-15-11), a team playing for pride and jobs next year after firing its head coach this week. The Western Conference bottom feeders are also looking to end a 13-game winless streak and are suiting up for their final outing at Buck Shaw Stadium before moving into new digs next season.
Needless to say, the hosts should have plenty of motivation.
"It's a tricky game for us because obviously they've just lost their manager, they're out of the playoffs and they've got nothing to lose," said Whitecaps head coach Carl Robinson. "We have got a lot to lose because we're in a good run of form at the moment and we're trying to challenge for the playoffs. It's a very difficult game for us, but the guys will be ready."
Vancouver has already beaten San Jose twice at home in 2014, but road games are a different beast in MLS, regardless of the perceived level of competition.
"Going to San Jose, a little bit of a wounded animal, is not going to be easy," said Whitecaps goalkeeper David Ousted. "We've played some good games, but now is the time to continue the good form and go in and still show that even though we're happy with the last three games we're not done working."
Vancouver and Portland are tied on points for the fifth and final playoff spot in the Western Conference after the Timbers had to settle for a disappointing scoreless draw at home against Real Salt Lake on Friday night. The result is a massive boost for the Whitecaps, who have two games left on the schedule to Portland's one.
"It's about catching your form at the right time and I think we've done that in the last three games," Robinson said prior to Friday's action. "We've still got two games to go. There's always one team that gets in the playoffs late that no one probably expects, and no one probably expected us a few games ago if I'm being honest."
Vancouver will be without defender Kendall Waston because of yellow card accumulation, but midfielder/striker Sebastian Fernandez is available after a one-game ban.
O'Brien — who has formed a good partnership with Waston — doesn't have a contract for next season, but said he plans to continue his playing career in 2015 if the Whitecaps or another team want him.
For now though, all he's worried about is Saturday's game in San Jose.
"We've got to concentrate on our job in hand, which is try to get the right result," said O'Brien. "Destiny is in our own hands. We've talked enough about it. We're coming down to the nitty gritty stage now."
Notes: Johnny Leveron looks set to replace Waston alongside O'Brien in defence. Leveron started 12 straight games for Vancouver in July and August before picking up an injury while on international duty with Honduras. ... Fernandez scored twice in Vancouver's 2-0 win over FC Dallas on Oct. 4. ... Houston Dynamo head coach Dominic Kinnear will lead San Jose next season after the Earthquakes fired Mark Watson and assistant Nick Dasovic on Wednesday. San Jose assistant Ian Russell survived the cull and will serve as interim head coach for the final two games of the season prior to Kinnear taking over. ... Watson and Dasovic are both former members of the Canadian national team. ... San Jose has not won since Aug. 2, a 1-0 home victory over Seattle. ... Vancouver's final game of the regular season is at B.C. Place Stadium on Oct. 25 against the Colorado Rapids, while Portland visits Dallas the same day.
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