This didn't sit well with Paul Pierce, who was scheduled to have his No. 34 jersey retired that day.
"Danny tried to sell me on it, but I told him, 'He had a shot, Danny, and he punked you on it. He pretty much dictated everything,'" Pierce explained, per Jackie MacMullan and Chris Forsberg of ESPN. "They let it happen because they felt sorry how (the trade to Cleveland) went down. It's guilt. That's what it is."
Thomas had spent three years with the Celtics, earning two All-Star appearances while leading the team to the Eastern Conference Finals last year. However, he was traded in the offseason in a package that landed Kyrie Irving.
Thomas was obviously upset with the deal, telling Sports Illustrated's Lee Jenkins later he may never speak to general manager Danny Ainge again.
The Celtics have since attempted to honor him with a video tribute, but the guard declined the offer on Twitter Tuesday, instead allowing Pierce to have the day all to himself.
Pierce, who was the 2008 NBA Finals MVP and earned 10 All-Star appearances in his 15 seasons with the Celtics, has had objections with the overlap since the change was initially made.
Meanwhile, his former Celtics teammate Rajon Rondo had a problem with Thomas being honored in the first place.
"What has he done?" Rondo asked, per Bill Doyle of the Worcester Telegram & Gazette.
Ainge listened to the complaints and helped create the change.
"It was only going to be during that segment," he said, per MacMullan and Forsberg. "During the rest of the game, it was going to be all Paul Pierce. But, after listening to Paul's perspective, I understood it and shared it with Isaiah and he understood it, too."
Although Thomas does deserve some admiration for his effort over the past few years before being traded, it's clear Pierce is a bigger part of the organization and will get his way.