Charania reports the rookie has a Grade 3 left ankle sprain and will continue to be re-evaluated.
Ionescu appeared to roll her ankle near mid-court while trying to avoid defensive pressure in the first half of Friday night's game against the Atlanta Dream. Ionescu needed to be helped off the court and could not put enough weight on her ankle to walk.
The news is a huge blow to the Liberty's roster. Ionescu struggled in her WNBA debut earlier this month, but quickly bounced back and dropped 33 points, seven rebounds and seven assists in her second game.
The No. 1 overall pick in the 2020 draft, Ionescu won nearly every individual honor in college basketball during her career at Oregon. She recorded the most career triple-doubles in college basketball history, won the John R. Wooden Award twice and is the only NCAA Division I basketball player to record 2,000 points, 1,000 assists and 1,000 rebounds in a career.