The 34-year-old surprised many experts when he finished in the top three two weeks ago at the Olympic trials in Houston. He set his personal best time several years ago in Chicago, which is one of the reasons he came back to encourage runners to sign up for this year's marathon.
"It's the city, the community, the organizers that make it a great marathon and the crowd along the course," said Abdi Abdirahman, U.S. Olympic Team.
Earlier in the day, Abdirahman spoke to student athletes at the Latin School.
Born in Somalia, Abdirahman's family moved to the U.S. to escape the civil war there when he was 11. He was happy to share his experiences with runners gathered at the Fleet Feet store for Tuesday's event.
It's nine months before runners will be hitting the streets for this year's edition of the Bank of America Chicago Marathon, but they're getting a jump on training. Organizers are giving them a chance to register early. Last year's race sold out all 45,000 spots in 31 days.
"I was one of those people last year at midnight with my computer," said Kristin Huenink, marathon runner.
"It's growing so fast, marathons have been selling out. You can't take any chances," said Joe Kiefer, marathon runner.
"It's become a social phenomenon," said Carey Pinkowski, Bank of American Chicago Marathon. "The city has embraced it. The neighborhoods have taken great pride."
Last year almost 17,000 people signed up in the first 24 hours after registration opened up. Organizers are expecting an even greater response this year. Registration officially opens at noon Wednesday.