Question: The head coach during the 1997–98 Indiana Pacers season retired as a player from what NBA team?
Context: The 2004–05 NBA season was the Pacers' 29th season in the National Basketball Association, and 38th season as a franchise.  The Pacers finished third in the Central Division with a 44–38 record.  This season also marked the final season for All-Star guard Reggie Miller.  (See "2004–05 Indiana Pacers season#Regular Season") The 2012–13 Indiana Pacers season was Indiana's 46th season as a franchise and 37th season in the NBA.  The regular season ended with a 49–32 win–loss record and the team advanced to the conference finals.  However, it was not to be as they fell to the Miami Heat in seven games.  The Heat would go on to win its third NBA Championship after defeating the San Antonio Spurs in a seven-game NBA Finals series. The 1997–98 NBA season was the Pacers' 22nd season in the National Basketball Association, and 31st season as a franchise.  It was also Larry Bird's first year as head coach.  During the offseason, the Pacers acquired All-Star forward Chris Mullin from the Golden State Warriors.  The team struggled early in the season losing five of their first seven games, but then won 15 of their next 18 games.  The Pacers won nine of their final eleven games, and returned to the playoffs after a one-year absence finishing second in the Central Division with a 58–24 record.  It was also the first time since joining the NBA that the Pacers finished with a winning road record.  Reggie Miller, Rik Smits and coach Bird represented the Eastern Conference during the 1998 NBA All-Star Game.  It was Smits' only All-Star appearance.  Bird was also named Coach of The Year. The 2016–17 Indiana Pacers season was Indiana's 50th season as a franchise and 41st season in the NBA.  On May 5, 2016, despite making the playoffs, Pacers' president Larry Bird announced that Frank Vogel's contract would not be renewed, citing a need for "a new voice" to lead the players.  On May 16, 2016, the Pacers promoted their assistant head coach Nate McMillan to become their new head coach. The 2011–12 Indiana Pacers season was Indiana's 45th season as a franchise and 36th season in the NBA.  The Pacers finished the regular season with a 42–24 record and secured a spot in the 2012 NBA Playoffs as the 3rd best team in the Eastern Conference.  After eliminating the Orlando Magic in the first round, Indiana lost in the East semifinals series against the Miami Heat in six games. Larry Joe Bird (born December 7, 1956) is an American professional basketball executive, former coach and former player, most recently serving as president of the Indiana Pacers in the National Basketball Association (NBA).  Since retiring as a player for the Boston Celtics, he was a mainstay in the Indiana Pacers organization, but stepped down from the position of president following the first-round of the 2017 Eastern Conference playoffs. The 1996–97 NBA season was the Nuggets' 21st season in the National Basketball Association, and 30th season as a franchise.  In the offseason, the Nuggets acquired Mark Jackson and Ricky Pierce from the Indiana Pacers, and signed free agent Ervin Johnson.  However, after a 4–9 start to the season, Bernie Bickerstaff was forced out as head coach and replaced with Dick Motta, where the Nuggets then lost ten straight games along the way.  Midway through the season, Jackson was traded back to the Indiana Pacers, while Pierce was dealt to the Charlotte Hornets.  Meanwhile, the Nuggets signed free agent Kenny Smith, who won championships with the Houston Rockets.  As the season drew, the Nuggets still struggled losing 26 of their final 30 games, finishing fifth in the Midwest Division with a 21–61 record.  Despite playing just 55 games due to a knee injury and a ruptured achilles tendon, LaPhonso Ellis led the team in scoring with a career high of 21.9 points per game. The 2012–13 Miami Heat season was the franchise's 25th season in the National Basketball Association (NBA).  They came into the season as the defending NBA champions, back-to-back Eastern Conference champions, the third season playing with the "Big Three" of Dwyane Wade, LeBron James, and Chris Bosh, and the fifth season under head coach Erik Spoelstra.  During the season, the Heat embarked on a 27-game winning streak, which still ranks as the 3rd longest winning streak in a single season in NBA history.  On June 3, 2013, the Heat defeated the Indiana Pacers in game seven of the Eastern Conference Finals to become the first team since the Chicago Bulls in 1998 to Three-peat as Eastern Conference champions.  The Heat then defeated the San Antonio Spurs in an NBA Finals that went the full seven games, handing the Spurs their very first loss in the NBA Finals, and with this victory in the NBA Finals, it echoed the 1997-98 Bulls as they had also been the last Eastern team to repeat as NBA champions. The 2006-07 Indiana Pacers season was Indiana's 31st season in the NBA and 40th season as a franchise.  They began the season hoping to improve upon their 41-41 output from the previous season.  However, they came six wins shy of tying it, finishing 35-47.  The Pacers would miss the playoffs for the first time since 1996-97. The 2014–15 Indiana Pacers season was Indiana's 48th season as a franchise and 39th season in the NBA.  The Pacers finished fourth in Central Division and ninth in Eastern Conference.  The Pacers missed the playoffs for the first time since 2010 after a 56–26 mark from the previous season, following two-straight Eastern Conference Finals appearances.  Before the start of the season, storm clouds gathered around All-Star Paul George, who seriously injured his leg during a Team USA scrimmage.  The injury required immediate surgery.  George was originally to be ruled out for the entire season, but as the season progressed, he was talking about returning.  He also announced before the season that he would be wearing number 13 and earned the nickname 'PG-13' (his initials and new jersey number).  As the season winded down and after months of rehabilitation, George made his regular season debut on April 5 in a home game against the Miami Heat.  He finished the game with 13 points off the bench and received a standing ovation.  His season ended, however, on April 16 when he strained his left calf in a game against Memphis.  George was only able to play six games this season.
Answer: Boston Celtics