South Boston's annual St. Patrick's Day parade may welcome a gay rights group for the first time in its history.

Boston Mayor Martin J. Walsh on Saturday said that he was “optimistic that a solution can be reached.”

Walsh had earlier threatened to boycott the parade if gay groups were not included in this year's parade – the second largest in the nation after New York's parade, which also excludes gay groups.

Under terms of the tentative deal, marchers may not wear T-shirts or carry signs identifying them as gay. Instead, gay rights advocate MassEquality could march under its banner.

The proviso didn't sit well with the organization, which said in a statement that “LGBT people should not have to silence who they are to celebrate other parts of their identities.”

Meanwhile, New York Mayor Bill de Blasio has traded in marching in New York City's March 17th St. Patrick's Day parade for participating in today's 15th annual St. Pat's For All Parade, an LGBT-inclusive parade.