Just days before the start of the season, the Celtics were dealt an emotional blow when their patriarch Red Auerbach died at the age of 89. When the season started, the days of Auerbach seemed like a distant memory as the Celtics lost six of their first seven games en route to a 5–13 start. In December, the Celtics improved their play as they embarked on a 5-game winning streak. However, after losing All-StarPaul Pierce to a stress reaction in his left foot on December 20, the Celtics crumbled, winning just 3 of their next 42 games, including a franchise record 18-game losing streak that lasted from January 5 to February 14, and plunging into last place. In between the losing streak, the Celtics lost Tony Allen for the remainder of the season, who tore both the ACL and MCL on January 10.
Adding to the pain was the death of another Celtics legend, Dennis Johnson, who suffered a heart attack on February 22 at the age of 52 while coaching the Celtics NBDL affiliate, the Austin Toros. After Pierce had returned in early February after spending 7 weeks on the injured list, the Celtics played better and won 5 of 6 games in late February and early March. A few weeks later on St. Patrick's Day, the Celtics stunned the eventual NBA championsSan Antonio Spurs 91-85 on the road, making it the first time the Celtics won against Tim Duncan, whom they missed out on during the 1997 Draft Lottery.
But nagging injuries would continue to hamper Pierce, who sat out all of April, as the Celtics finished with a horrible 24-58 record that earned them the worst record in the Eastern Conference and 2nd worst record in the league, only marginally in front of the Memphis Grizzlies. Afterwards, the Celtics turned their focus to the draft lottery, where they had good chances of landing a Top 2 pick, allowing them to select either Greg Oden or Kevin Durant. However, even the draft lottery came out all wrong for the Celtics as they were assigned the 5th overall selection, which seemed to guarantee another disappointing season.