The Islanders are closing in on an agreement to play a mix of the team’s regular-season games at Barclays Center and Nassau Coliseum in the years leading up to the opening of the new arena at Belmont Park, according to two people familiar with the situation. It is not yet known how the games will be structured. The Islanders have been negotiating with Brooklyn Sports & Entertainment, which operates both arenas, in the weeks since Gov. Andrew M. Cuomo announced the Islanders’ bid to develop an arena at Belmont was selected as the winner. The Islanders and Brooklyn Sports & Entertainment have until Jan. 30 to complete the opt-out process. Islanders co-owner Jon Ledecky said on WFAN Jan. 10 that he was “confident something would be worked out” regarding some games being played at the Coliseum. NHL commissioner Gary Bettman and other league officials toured the renovated arena Jan. 9 alongside Ledecky and Brooklyn Sports & Entertainment CEO Brett Yormark to assess its viability in the short-term.