DiPietro was injured at 5:40 of the second period. After talking to the Islanders' trainer, the netminder left the ice and went straight to the locker room.
DiPietro departed having stopped 13 of 14 shots with the Islanders leading 4-1.
After the game, DiPietro described his injury as a "little tweak" and wasn't sure how long he would be out -- if at all. He will be re-examined Tuesday.
He hurt himself sliding across the crease to try to stop a shot from Jarome Iginla, which whistled off the crossbar.
"I don't know if a man's body is supposed to be contorted in those kind of positions," said DiPietro, who was facing a barrage of pressure during a Flames power play at the time. "I felt a twinge and hopefully it's nothing serious."
Calgary native Nathan Lawson, who was recalled from Bridgeport of the American Hockey League after the Islanders traded Dwayne Roloson to Tampa Bay on Saturday, replaced DiPietro in goal for New York.
DiPietro had recently missed time with left knee swelling, coming off a short stint on injured reserve to make 37 saves in the Islanders' 2-1 victory over Pittsburgh on Dec. 29.