He has also played in the National Basketball Association with the Los Angeles Clippers, Seattle SuperSonics, Oklahoma City Thunder, New York Knicks and Detroit Pistons. While at Whiteville High School in Whiteville, North Carolina, he led the basketball team to the 2A State Championship in 1999, before transferring to William G. Enloe High School in Raleigh, North Carolina for his senior year. Wilcox was drafted by the Los Angeles Clippers in 2002.
He was traded on February 14, 2006, to the Seattle SuperSonics in exchange for Vladimir Radmanović.
While playing for the Sonics in 2005–2006, Wilcox averaged 14.1 points per game and 8.2 rebounds per game. He was on the starting lineup for 23 of his 29 games with the Sonics that season.
Wilcox"s rebound total was the most by a Sonic player since Jack Sikma grabbed 25 at Utah on February 10, 1983. On February 19, 2009, Wilcox was traded to the New York Knicks for Malik Rose.
On July 22, 2009, Wilcox signed a multi-year contract with the Detroit Pistons.
On December 9, 2011, Wilcox agreed to a contract with the Boston Celtics for the midlevel exception ($3 million). After being diagnosed with a heart irregularity, he was waived by the Celtics on March 23, 2012. However, Wilcox was later cleared to play, and he re-signed with the Celtics on July 14, 2012.