Horford (toe/rest) has been ruled out for Monday's game against the Pistons, Taylor Snow of the Celtics' official site reports.
As expected, Horford will take a seat for the second half of a back-to-back set after posting 14 points (5-7 FG, 2-4 3Pt, 2-2 FT), four rebounds and two assists in 23 minutes during Sunday's 130-104 win over the Wizards. Kristaps Porzingis (hamstring) is slated to return from a five-game absence and should start at center while Horford is in street clothes.