Clifford said a timetable for Zeller's return might be known later Saturday night. It's the same shoulder Zeller had operated on earlier this year and kept him sidelined for a few months.
Zeller is one of five key players out for the Hornets. Guard Nic Batum (toe), guard Jeremy Lamb (toe), center Al Jefferson (knee) and forward Michael Kidd-Gilchrist (shoulder) also are out with injuries.
Zeller was injured earlier this week against Oklahoma City and did not play against Orlando on Friday night.
Knicks forward Lance Thomas will miss his second straight game with a sore left knee.