DiPietro was hurt during the first period of a March 13 loss against Montreal after colliding with Canadiens forward Steve Begin. Begin's skate struck the goaltender in the head.
The Islanders lost the next two games while DiPietro sat out, but he has played the last four contests -- a shootout loss, two wins and an overtime loss to the New York Rangers Sunday.
"After the game on Sunday, Rick told our medical staff that he was suffering from headaches," said Islanders GM Garth Snow. "Until Rick is completely recovered, he will not play. As important as these games are, nothing is more important than Rick's health."
The Islanders entered Tuesday's game against New Jersey tied with Montreal and Carolina for the last playoff spot in the Eastern Conference. They were two points behind seventh-place Tampa Bay, three behind the sixth-place Rangers.