An MRI performed Friday revealed a strained left plantar fascia.
Camby missed 12 consecutive games earlier in the season with a similar ailment.
"It's another setback, but we've got to keep it moving," Knicks coach Mike Woodson said. "We'll get him back rehabbed again and then try to get him back out on the floor when we can."
Camby had started the past four games for the Knicks and was starting to shake off the rust from his prolonged absence. Woodson liked the combination of Camby and Tyson Chandler on the same front line.
With Camby out for Friday's 108-101 loss to the Chicago Bulls, Woodson started Jason Kidd at point guard, James White at shooting guard, Carmelo Anthony at small forward, Kurt Thomas at power forward and Chandler at center.
Amar'e Stoudemire played in back-to-back games for the first time this season is a positive sign in his comeback from left knee surgery, yet also an indication of how depleted the Knicks are because of injuries.
Camby, 38, left the Knicks' locker room in a walking boot and crutches on Thursday after their loss in Indiana.
"I did something to my foot again like I did earlier in the year ... I drove and felt a sharp pain in the bottom of my foot similar to before," Camby told reporters in Indianapolis.
Camby was in the midst of his best game of the season on Thursday. He had seven points and seven rebounds in 19:34 before exiting in the third quarter.
With Camby and Rasheed Wallace (stress reaction in left foot) out, the Knicks may turn to the free-agent market to find a veteran big man.
A league source confirmed on Tuesday a Yahoo! Sports report that the Knicks had discussed internally the possibility of adding 35-year-old free agent Kenyon Martin.
The Knicks, according to a league source, had not reached out to Martin's representatives as of Friday evening. Woodson dismissed the Knicks' interest in Martin.
When asked about the possibility of New York (23-12) adding a free agent, Woodson said he hadn't spoken with ownership and that general manager Glen Grunwald and the team would "sit tight" for the time being.
Ian Begley is a special contributor to ESPNNewYork.com.