But Bairu is no quitter.
The 29-year-old from Regina will run the NYC Marathon on Sunday in his quest to conquer the killer 42.195-kilometre race that has twice knocked him down.
"I look at it as a challenge, I have enough confidence in myself to know that New York could go terribly wrong again ... but if I get to the point where I'm scared of competition, I'll just move on to something else," Bairu said from his home in Portland.
"I'm excited to just get out there and prove to myself more importantly than to prove to other people that I can do it."
The Canadian record-holder in the 10,000 metres was pegged as a future marathon star. But his debut two years ago — in the same New York City race he'll run Sunday — went horribly wrong when he collapsed about five kilometres from the finish and had to be taken by ambulance to hospital.
His second attempt was more of an emotional blow than a physical one — but at least as painful nonetheless.
He was gunning for Canada's Olympic standard of two hours 11 minutes 30 seconds at the Houston Marathon last January, and was on pace through 30 kilometres before "the wheels fell off" with five kilometres to go. He finished in 2:19.52.
"After the race, what was devastating was I really thought that was going to be the last marathon I ever ran," Bairu said. "Because my body — I broke down. The last three miles, I probably averaged eight-, nine-minute pace. It was ugly.
"It was definitely tough and after that, not even going to the Olympics made the summer pretty brutal for me. It was definitely a long, long summer."
Bairu had one more shot at Canada's team for London in the 10,000 metres. But still dealing with the physical toll of his marathons, missed the qualifying standard by 13 seconds.
He went home to Regina for the summer, and didn't watch any of the Olympics.
"I called or texted or sent emails to the guys I know representing Canada, and I wished them all the best, because we're all friends," Bairu said. "But personally I couldn't get myself around actually watching the Olympics, it was a constant reminder of how much I had failed, and that's how I looked at it. I should have been there.
"I tried to avoid it, but it was one of those things where it was completely in my face the whole time," he added. "It just made me realize, four years ago I thought I was going to be in London right now ... it was definitely really depressing."
Canada had three men run the marathon there for the first time since 1996 — Dylan Wykes, who finished 20th, Eric Gillis (22nd), and Reid Coolsaet (27th).
Bairu finally received a stern talking-to from his dad Yehdego.
"Basically told me to suck it up," Bairu said. "I really needed it. I was starting to feel sorry for myself."
Bairu decided then and there that he wouldn't let his career end that way. He called up coach Jerry Schumacher and said, "Jerry, if we can figure out what's wrong with me, and if we can fix this, I want to run the New York City Marathon."
"He thought that was ridiculous," Bairu said with a laugh. "We didn't know where we were going with our running, if I was even going to be training. But he was like, 'Alright, I'm not going to say no, but I'm not going to say yes. We're just going to feel it out and in the last couple of weeks before the race I'll make a decision based on what I see.'"
What they figured out after several visits to doctors is that his collapse in the New York race had taken a huge physical toll that he hadn't fully recovered from.
His training has been going well, he said, and last month he won the San Jose Half-Marathon in 63:28.
"I know a half marathon isn't a good indication of where you are in a marathon, but just to see where I was at, if I was at least able to run the entire race, maintain control of my body, and just feel good ... which is something I haven't done in a long time unfortunately — finish a race feeling good."
He isn't gunning for a particular time or placing on Sunday in an event that had appeared in doubt due to damage from this week's storm. Bairu has nearly four years before the 2016 Olympics to gain experience over the distance.
Finishing without a major calamity would be nice.
"Honestly, I'm a 2:19 guy on paper, and that's the best approach that I can take, and I'm just going to try to chip away at that time, by two, three minutes at a time," Bairu said. "And hopefully by 2016 I'll be where I was hoping to be this past year."
Bairu knows there will be plenty of people in Canada's large running community keeping an eye on his time Sunday. He doesn't mind.
"Actually the support has been amazing over the past year," he said. "It's one of the first things I saw after Houston was my Facebook and email was just flooded, half the people I didn't even know, just telling me to keep my head up, wishing me well — that type of stuff really does help.
"It was really nice to know that there's people out there rooting for you."