Felton aggravated a pre-existing left hamstring injury in the third quarter against Cleveland on Tuesday while driving to the basket. He was removed from the game shortly thereafter and never returned. Felton also missed Wednesday's win over the Bulls.
An MRI taken Thursday confirmed the injury.
With Felton out, the Knicks will likely rely heavily on Pablo Prigioni and Beno Udrih to fill in at point guard. Felton has been playing with hamstring and hip soreness for much of the season. He first injured his hamstring in the preseason and missed four games late last month due to both ailments.
Felton is averaging 10.3 points and 5.2 assists in 32 minutes this season while shooting 39 percent from the field.
In other injury news, the Knicks say guard Iman Shumpert is day to day with a bruised left knee. Shumpert appeared to injure his knee in a collision with Chicago's Mike Dunleavy early in the third quarter. He went to the locker room immediately after the collision and did not return.
Any issue involving Shumpert's left knee is a cause for concern. He had surgery to repair ACL and meniscus tears in his left knee in April 2012. He then had a second surgical procedure on the same knee in the offseason.
Ian Begley is a regular contributor to ESPNNewYork.com.