The team previously relayed that Brown had worked out during Thursday morning's shootaround and would "test his calf again" before the game in L.A.
The 23-year-old guard had suffered the injury when Russell Westbrook kneed his calf as both players went for a rebound in the fourth quarter of Boston's 116-105 loss to the Houston Rockets Tuesday night.
Brown has been one of the central figures for a Boston team locked in a battle with the Toronto Raptors for the top spot in the Atlantic Division.
Now in his fourth season, Brown is averaging career highs in points (20.2), rebounds (6.4), assists (2.2) and steals (1.1) per game. He's also shooting 49.5 percent from the field and 38.1 percent from three-point range.
The Celtics haven't had a lot of injury concerns this season, with the exception of Gordon Hayward fracturing his left hand in November. Kemba Walker has dealt with lingering knee soreness dating back to a Jan. 30 game against the Golden State Warriors.
As long as Brown doesn't have to miss an extended period of time, Boston will be able to maintain its position in the Eastern Conference playoff standings. Head coach Brad Stevens will likely turn to Marcus Smart in the starting lineup until Brown can return.