Davenport was to have played Gisela Dulko, who was given a walkover into the Grand Slam event's third round. Dulko has never advanced past the third round at Wimbledon.
Davenport, ranked 25th in the world, missed the last two Wimbledon's because of injury in 2006 and pregnancy last year. She won the event in 1999 and was the runner-up in 2000 and 2005.
The knee injury forced Davenport's withdrawal from the Wimbledon tuneup event at Eastbourne, England. She defeated Renata Voracova 6-3, 5-7, 6-3 in her Wimbledon first-round match Tuesday but needed medical attention during the match.