The Boston Celtics have concerns about potential tampering on Al Horford ahead of free agency. The Celtics expected to negotiate a new deal with Horford when he opted out of his contract for the 19-20 season, but talks quickly broke down. Horford eventually signed with the Philadelphia 76ers.

"I don't know if you heard this, but the Celtics were, from what I am told, one of the teams that kind of stomped their feet about what they felt was tampering," said Brian Windhorst on The Hoop Collective Podcast. "Not with Kyrie, although that looked like it was lined up pretty far in advance, but with Horford.

"What happened with Horford, again from what I'm told, really upset the Celtics. They were thinking they were going to be able to negotiate with him.