Anthony experienced the back issues in the first half of Monday's 91-86 loss at Houston. The Knicks finish a three-game road trip at Oklahoma City on Friday. Anthony's status for that game is unclear.
Before re-signing with New York in the offseason, Anthony made stops in Houston and Dallas on his tour in free agency.
Anthony started the day sixth in scoring in the NBA at 23.2 points per game.
J.R. Smith made his third start of the season in Anthony's spot.