It has not been an easy season for the Mets, who are lurching toward the All-Star break with a losing record. Opposition has come in the form of hard-throwing pitchers, mounting injuries and marathon-length games, but the team suddenly finds itself facing heat from an unexpected source: an American Indian organization.

When the Mets approached the American Indian Community House, a New York-based nonprofit organization, in March about helping to organize a Native American Heritage Day, the proposal struck members of the group as a good opportunity to celebrate their involvement in the community. A date was selected — July 25 — and they began to plan pregame festivities that would include traditional dancing and singing outside Citi Field.

But there was a glitch, as far as the Mets were concerned: they were scheduled to host the Atlanta Braves that day. So in the past week, concerned that such activities might be interpreted by the Braves organization as a form of protest over its nickname, the Mets drastically reduced the day’s activities: no singing, no dancing. And now there won’t be any American Indians, either.

On Monday, the A.I.C.H. pulled out of the event, citing frustration with the Mets for thwarting months of planning. The team has removed the event from its online schedule of activities.