Josh Hart and the New York Knicks have agreed to extend a midnight ET deadline on Saturday for his $12.9 million player option until Thursday, sources told ESPN.

Hart, a priority to retain on a new deal, could opt-in and extend off that $12.9 million number for next season or decline the option and become an unrestricted free agent eligible to sign a new deal with the Knicks or another team.

An option for Hart that would deliver the Knicks salary cap flexibility would be an opt-in and extension off his $12.9 million salary for next season — which he is eligible to do for up to 140 percent of that salary. This would give the Knicks access to using their full $12.4 million non-tax payer mid-level exception. The Knicks have $149 million in guaranteed salary on the books for next season, which is $16 million below the luxury tax level.