Canada's Davis Cup Finals hopes suffered a blow when Milos Raonic withdrew from the team on Monday with a back injury.
The 28-year-old former world number three will be replaced by 94th-ranked Brayden Schnur for the week-long event in Madrid.
"It is very hard and disappointing for me that I will not be able to represent my country at Davis Cup," he said in a statement issued by Tennis Canada.
"My health has continued to let me down through this entire year and now once again. I will take the appropriate time to get healthy and I look forward to being back on court next season."
Even without Raonic, Canada have a strong squad with world number 15 Denis Shapovalov and fellow youngster Felix Auger-Aliassime, ranked 21st, both making the trip.
Canada are one of 18 nations contesting the first edition of the Davis Cup since its radical revamp.
They will be in Group F with the US and Italy.
"I believe in my team mates, and I know they'll give everything to secure Canada's first Davis Cup title.
"I'll be following them very closely and I wish them the best," former Wimbledon runner-up Raonic said.
Ties will consist of two singles and a doubles with the top team from each group and two best runners-up progressing to the quarter-finals. Round-robin matches begin on Monday with the final on Sunday November 24.(This story has not been edited by News18 staff and is published from a syndicated news agency feed)