"I'm going to play no matter what, even if I'm on one leg," said Bouchard, who was losing 6-4, 3-0 to Belinda Bencic of Switzerland when she retired.
The player who beat Bouchard in last year's Wimbledon final, Petra Kvitova, pulled out of Eastbourne on Monday because of illness.
Bouchard said she started feeling the abdominal muscle injury during the first set against Bencic.
"I kept trying and trying," the Westmount, Que., native said. "I mean, at the end it was hard for me to put a serve in, just because I felt that pain a little bit.
"It just wasn't smart for me to take a risk, and potentially be out for a long time. It's something I want to kind of take care of right away."
Bouchard said the injury was "something I have had in the past," and intends to take a few days off from serving.
It's been a difficult year for Bouchard, who has slipped out of the top-10 in the world rankings after a string of disappointing results. She has just three wins since her quarter-final loss to Maria Sharapova at the Australian Open in January.