 Complete the following phrase:  On June 26, the Celtics selected shooting guard J. R. Giddens with the 30th and center Semih Erden with the 60th overall picks in the 2008 NBA draft, and traded cash considerations in exchange for small forward Bill Walker, who had been selected by the Washington Wizards with the 47th overall pick. Giddens had worked out with the Celtics before the draft for three days, and received praises from head coach Doc Rivers, who thought he could fight for minutes on the team right away. He was already familiar with future teammates Leon Powe and Kendrick Perkins, who were his teammates at the 2003 McDonalds High School All-American Game. Walker was considered a lottery pick, but suffered the third knee injury in his career during a workout at the Golden State Warriors facility on June 15. However, he remained in the draft despite the injury, and was expected to have minor surgery in July that would keep him out for three to four weeks. Erden was not expected to join the roster this season, and was seen by general manager Danny Ainge as their first-round pick in 