Rizzo was diagnosed with a fractured finger after leaving Saturday's game against the Pirates, Bryan Hoch of MLB.com reports.
Rizzo suffered the injury after getting hit in the hand by a pitch during the seventh inning. Manager Aaron Boone said after the game that Rizzo's injury doesn't necessarily rule him out for the start of New York's playoff run, and the first baseman's availability will depend on pain tolerance. That being said, it's likely he sits out Sunday's regular-season finale.