Isaiah Thomas has been spending most of his time recently at the end of the Denver Nuggets bench.

That hasn't stopped speculation about Thomas potentially returning to the Boston Celtics as a free agent this summer. 

"You never know," Thomas said, per Adam Himmelsbach of the Boston Globe. "You can't predict the future. My options are always open for anybody. I'm a Denver Nugget now, but I'm a free agent at the end of the season, and you never know what can happen. Who knows?"

The Celtics traded Thomas to the Cleveland Cavaliers in July 2017 as part of the deal that brought Kyrie Irving to Boston. At the time, Thomas was coming off a star-making season that saw him become a second-team All-NBA selection.

A hip injury, which was initially suffered during the 2016-17 campaign, has derailed Thomas' career the last two seasons. He's played in just nine games for the Nuggets this season and has been a healthy DNP the last three games, a trend that will likely continue the remainder of the year.

The Celtics host Denver on Monday night, and Thomas will undoubtedly receive a warm reception from the TD Garden crowd.

While his trade was seen as one of the most ruthless (albeit correct) business decisions in recent NBA memory—Thomas' hip issues were caused by him playing through an injury for the Celtics, and he also continued playing for the team following the tragic death of his sister—the city of Boston and Thomas have a strong bond. 

"What happened in Boston happened for a reason, and that love's going to last forever," Thomas said in a phone interview Sunday. "I was only here three years, but you'd think I was here 15 from the love that they showed me and the love that we gave each other. That's all genuine. It was a city that needed something at that time, and I needed a team that believed in me. I'm a hard-working guy and played with my all, and that's all the people here wanted. They expected greatness, and I wanted to show them greatness."

Thomas said he still speaks with coach Brad Stevens "about once a month." He still has relationships with other staffers in the building as well, many of whom helped him through the darkest time in his life. 

"That's probably the biggest thing for me, how this whole organization and city came together with me and were by my side when I grieved," Thomas said. "The love and what I feel for Boston will never change because of that."