Zuccarello turned away from a shot taken by Sabres defenseman Jordan Leopold at 8:48 on Friday night and was struck. After nudging the puck, he immediately skated to the bench - with his left arm hanging limply at his side - and gingerly climbed over the boards.
There were no other updates, and the Rangers said the 24-year-old Zuccarello would be out indefinitely.
The 5-foot-7 fan favorite was playing in his 10th Rangers game this season - his second in the NHL. Zuccarello had no points in the first three games of the season before being sent down to Connecticut of the AHL.
Zuccarello was recalled on March 11, and he had an assist that night in a victory over the New York Islanders. He scored goals in consecutive games against Colorado and New Jersey before being held off the score sheet in the Rangers' win over Detroit on Wednesday.