"Lauren has been playing with back pain for a couple of weeks," Seattle Storm coach Brian Agler said.
"She will rest and work with our team physicians and trainers to rehabilitate her back."
Jackson had a bone scan on Saturday Australian time that revealed the stress fracture, Agler said.
He says it's doubtful the Opals centre will travel with the team for a three-game road-trip that starts on Wednesday at New York.
Jackson had 17 points and played 29 minutes as the Storm beat the Connecticut Sun 86-74 last week to clinch a sixth consecutive playoff berth.
Jackson is the Storm's leading scorer averaging 19.2 points pre game.