Walsh won't start Game 1 of the opening-round series against the Heat on Sunday.
With Boston resting its usual starters, Walsh made his first career NBA start during the regular-season finale and posted one point (0-2 FG), three rebounds, two steals and an assist in 17 minutes during a win over Washington. The rookie spent most of the season in the G League and isn't expected to be part of the Celtics' postseason rotation.