The Hornets confirmed the injury on Thursday after Kidd-Gilchrist dislocated his right shoulder in Wednesday's 117-95 NBA win over the Indiana Pacers.
It was Kidd-Gilchrist's seventh game back after missing the first 46 matches of the season with the same injury suffered in the pre-season.
There is no timetable for Kidd-Gilchrist's return, with the 22-year-old to be re-evaluated after the All-Star break.
The former number two pick out of Kentucky has been averaging 12.7 points and 6.4 rebounds in the six-plus games he has played this season.