Love was ruled out with a concussion, which he suffered in the first quarter of Game 6. It's his second concussion of the 2017-18 season and third since 2016.
Green performed admirably in his stead, finishing with 14 points, three rebounds, two assists and two blocks in 31 minutes.
Lue could have started Kyle Korver, who has been the Cavs' third-best player in the playoffs. Korver had scored in double figures in six of his previous eight postseason games before combining for 13 in Games 5 and 6. Lue took heat for failing to play Korver in the first quarter of Cleveland's Game 5 loss in Boston.
Korver has the best net rating of any Cavs rotation player during the postseason, per NBA.com. In the Celtics series, though, Cleveland has outscored Boston by 0.8 points per 100 possessions with Green on the floor versus being outscored by exactly as many with Korver playing.
The stats do technically favor Lue's decision here, though there's going to be fair criticism over keeping what amounts to his second-best player on the bench.
With Love out, the Cavs are going to need a historic performance from LeBron James and for one of their rotation players to produce. Lue needs to hope it's Green, or he'll come under fire later Sunday night if the Cavs lose.