According to Marc Stein, the Boston Celtics are interested in a reunion with former draftee Kelly Olynyk. Similar to other names we've heard the Celtics having interest in, the main issue remains that the Celtics don't have the contracts or TPE to trade for a player making more than MLE money. Olynyk is making $12.2 million, so about twice as much as the Celtics largest TPE, which you can't combine with players in a deal.
Boston is not trading any of it's top 6 for Olynyk, so that means they'd have to part with Payton Pritchard and his contract and an additional player/contract or two to make the math work.