Lewis signed a deal with Seattle Tuesday for a reported five years and $75 million. He was sent to Orlando Wednesday for a future second-round draft pick.
"Rashard is a young, athletic forward and a proven scorer in this league," said Orlando General Manager Otis Smith. "We feel his skills will be a tremendous addition to our team."
Lewis, 27, averaged a career-best 22.4 points last season with Seattle, which found him to be expendable when the Sonics obtained Kevin Durant with the No. 2 selection in last week's draft.