Thanks to the 1984 trade of Gerald Henderson and the subsequent fall of the Seattle SuperSonics, at the end of the 1985–86 season the Celtics owned not only the best team in the NBA but also the second pick in the 1986 NBA Draft. The Celtics drafted Len Bias with the pick and had high hopes for the young Maryland Terrapins star. The hope was that his presence would ensure that the franchise would remain a powerhouse after Bird, McHale, and Parish retired. Unfortunately, Bias died 48 hours after he was drafted, after using cocaine at a party and overdosing.

Unlike the prior year, the Celtics were forced to endure major injuries to several key players including Bill Walton, Kevin McHale and Robert Parish. With a road record of 20–21, the Celtics were a sub-.500 road team for the first time in the Larry Bird era and the first time since the 1978–79 season. However, they continued with the previous season's historic dominance at home with a record of 39–2 at Boston Garden.

Note: GP= Games played; REB= Rebounds; AST= Assists; STL = Steals; BLK = Blocks; PTS = Points; AVG = Scoring Average

(1) Boston Celtics vs. (8) Chicago Bulls: Celtics win series 3–0

(1) Boston Celtics vs. (4) Milwaukee Bucks Celtics win series 4–3

(1) Boston Celtics vs. (3) Detroit Pistons Celtics win series 4–3

Despite the loss of Bias, the Celtics remained competitive in 1986–87, going 59–23 and again winning the Eastern Conference Championship. Celtics ran into perhaps the best Los Angeles Lakers team of the "Showtime" era. The biggest injury was yet another foot injury for Bill Walton, who only played 10 regular season games in 1986–87 after playing 80 games the year before. Walton fought through the injury, playing 12 games (out of 23) in the playoffs, but was not the same player as he was the year before. Kevin McHale played on a broken foot through the playoffs. This combined with injuries to Parish and Ainge forced reserves Darren Daye and Fred Roberts to play larger roles in the series, which the Celtics would lose 4 games to 2.

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