Getty Boston Celtics star Jaylen Brown's stats without Jayson Tatum playing could determine Game 7 versus the Philadelphia 76ers. J ayson Tatum is not playing for the Boston Celtics against the Philadelphia 76ers in Game 7 after an initially unclear injury situation was officially listed as “left knee stiffness.” That puts the Celtics’ season directly in Jaylen Brown’s hands and shifts the Celtics’ starting lineup. Tatum was ruled out shortly before Boston’s winner-take-all matchup with