Boston, MA -- (Sports Network) - Boston Celtics center Kendrick Perkins underwent arthroscopic left shoulder surgery Wednesday.

Perkins was hurt during the NBA Finals against the Los Angeles Lakers. The exact nature of the procedure was not disclosed and no timetable has been given for his return.

The injury, which occurred in Game 4 of the Finals, was initially described as a strained left shoulder. He was hurt while trying to block a shot by the Lakers' Lamar Odom, then sat out Game 5 and returned for the clinching Game 6.

Perkins averaged 6.6 points and 6.1 rebounds in 25 playoff games this past spring after notching 6.9 points and 6.1 rebounds in 78 games during the regular season.

The Celtics also announced that draft pick Bill Walker had arthroscopic right knee surgery on Wednesday. Walker was selected with the 47th pick of the NBA Draft by Washington, then traded to the Celtics for cash considerations.

Walker, perhaps best known as Michael Beasley's teammate at Kansas State, started 28 of 31 games last season for the Wildcats and averaged 16.1 points with 6.3 rebounds.