Raonic, from Thornhill, Ont., will play in the second singles match of the day Friday after Vancouver's Vasek Pospisil opens the best-of-five tie against Santiago Giraldo.
The winner of the tie, which will be played on indoor hard court at the Halifax Metro Centre, will advance to the elite World Group next season. Canada is looking to reclaim its World Group spot after a first-round loss to Japan earlier this year.
After Friday's singles matches, Pospisil and Toronto's Daniel Nestor will play Juan Sebastian Cabal and Robert Farah in doubles. On Sunday, Raonic will take on Giraldo while Pospisil will play Gonzalez, a last-minute substitute for the injured Alejandro Falla. Frank Dancevic of Niagara Falls, Ont., is Canada's spare.
Raonic, ranked seventh in the world, hasn't played since losing a marathon fourth-round U.S. Open match to tournament runner-up Kei Nishikori of Japan. The Canadian said earlier this week that his body had recovered from the gruelling loss.
"Now that the draw is done, we are ready for the weekend and feel confident about our team," Canadian captain Martin Larendeau said. "Though we know Colombia will be fighting hard to make history for their country, we feel we belong in the World Group and will do whatever it takes to stay there."
At No. 8 in the world, Canada is seen as the favourite, though the 26th-ranked Colombians did win the last meeting between the two teams in 2010 and are looking for their first-ever World Group berth.
Canada made Davis Cup history last year by making the semifinals in 16-team World Group. A loss to Colombia would relegate the Canadians to Americas Zone Group I for the first time since 2011.