By Daniel Bates Center Robert Williams III has been an essential part to the Celtics’ torrid run to the top of the Eastern Conference standings. But with a double-double through three quarters, Boston‘s big limped off the court, only to never return. The team diagnosed Williams’ injury as a left knee sprain. But now, according to The Athletic’s Shams Charania, the Celtics’ defensive anchor is feared to have torn his meniscus. Per Charania, “Boston Celtics center Robert Williams is feared to have suffered a meniscus tear in his left knee…” Adding, “It could lead to an indefinite absence, which …