During their first stint as teammates, a younger Tatum was more focused on developing and learning from veterans like Horford. But one of the biggest differences that Horford has seen in returning to the Celtics this season, is that Tatum has now transitioned into that role of being a vocal, motivational leader. “He has taken a step forward in that regard,” said Horford. “He is being more vocal. He’s letting us know what he’s thinking, how he’s feeling. For me, it gives me a lot of confidence, and it’s encouraging to know that he has my back. He’s obviously really trying to win, he’s trying to do things the right way … Seeing him that excited, that engaged, it’s a good sign for our group.”