According Fox Sports' Jeff Goodman, the Celtics were the first team to make contact with free agent David Lee after the clock turned to 12:01 a.m. Thursday morning.
The 6-foot-9 Lee, 27, played in all 81 regular season games for the New York Knicks last season, averaging 20.2 points and 11.7 rebounds per game. It was Lee's best season, having averaged 13 points and 9.6 rebounds per contest throughout his five-year pro career.
David Lee has spent all five years in the NBA with the Knicks.