Bouchard, from Westmount, Que., was runner-up to 2014 winner Petra Kvitova while Raonic, from Thornhill, Ont., lost in the semi-finals to seven-time champion Roger Federer.
Twelve months later, Bouchard, 21, and Raonic, 24, enter the event with injury issues. Bouchard withdrew from a second-round match in Eastbourne last Wednesday with an abdominal strain and was unable to practice until Sunday.
She suffered a similar injury at the Indian Wells event in March, but recovered in a week before playing in Miami.
"I'm hoping for the same kind of turnaround here," she said Saturday.
Her first-round opponent on Tuesday will be six-foot-one, 185-pound Duan Ying-Ying, a 24-year-old Chinese qualifier ranked No. 117.
Raonic had surgery for an inflamed nerve in his right foot and missed the French Open, but he won two rounds in his return to action at the recent Queen's Club event in London.
"I've made great progress in the last 18 days," he said Saturday. "I feel good where I am now."
On Monday he faces Daniel Gimeno-Traver, a 29-year-old Spaniard ranked No. 62.
Bouchard has a strong history at Wimbledon - winning the 2012 Junior Girls title and beating Ana Ivanovic the following year in her Centre Court debut.
Raonic won only one Wimbledon match as a junior and did not get past the men's second round between 2011 and 2013. That changed last year.
"The grass can be quick and the biggest difference in the past was I hesitated to go for my shots," he said. "That was making me fall behind in points. Last year, every single practice I was serving as hard as I could, really making a habit of executing. I served great last year and think I know how to use that again this year."
Vancouver's Vasek Pospisil is also in singles. He plays French qualifier Vincent Millot on Tuesday.
The No. 8-ranked Raonic is 23-10 this year. Bouchard, No. 12, is 8-13 and in a highly-publicized 2-11 slump since March.
"It's tough to watch," Raonic said. "It hasn't been just her tennis, it's been injuries she's faced and so forth which most people don't pay attention to."
Bouchard said that past greats such as Chris Evert have reached out to help.
"When you don't win matches for a while you almost lose it and often feel like it's almost more normal to lose," she said. "I don't want that mentality."
"Things aren't perfect but maybe Wimbledon can revive me a little bit," she added about her chances this year at the All England Club.
Raonic sounded more positive, responding to a question about whether he can win Wimbledon with a confident "I believe so."