Celtics forwards Jeff Green and Brandon Bass appeared to exchange words on the Boston bench in the third quarter of Tuesday's 92-91 loss to the Atlanta Hawks at TD Garden. Broadcast video appears to show teammates and assistant coach Jay Larranaga trying to defuse the dust-up. Asked after the game about a potential squabble, first-year Celtics coach Brad Stevens said, "Disagreements are part of the game, it’s part of team basketball. But how quickly you move on from there says a lot." What had both players worked up? It was likely the struggles of Boston's first unit. The starters were minus-7 in plus/minus over 10 minutes together in the first half, allowing the Hawks to chip away at an 18-point advantage that the second unit helped build. When that lead further dissolved at the start of the second half, Stevens pulled his underperforming starters in favor of the second-unit frontcourt featuring Gerald Wallace, Kris Humphries and Kelly Olynyk.