Vasek Pospisil will replace Daniel Nestor on Canada's Davis Cup team for this weekend's Americas Zone Group I first round tie against Mexico.
Nestor is suffering from an inflamed Achilles tendon and needs temporary rest and treatment.
"I'm very disappointed that I can't be in Mexico with the team, but resting and treating my foot is the priority so that I ensure I don't miss any time," said Nestor in a statement Wednesday.
"It's, obviously, tough for me as I haven't missed a Davis Cup tie in about 10 years and I consider it a very important part of my schedule. I believe that the guys will do great and, hopefully, give me a chance to come back for a second round tie against Ecuador in July."
The Toronto native is third-ranked doubles player in the world and holds the record for most years played by a Canadian in Davis Cups at 18, most wins (42), most doubles wins (27) and most ties played (38).
Pospisil of Vernon, B.C., will be joining Frank Dancevic of Niagara Falls, Ont., Peter Polansky and Milos Raonic, both of Thornhill, Ont., on the team led by captain Martin Laurendeau of Montreal to face Mexico from March 4-6.