The Major League Soccer club announced that both parties had "mutually agreed to a contract termination".
Rangers manager Ally McCoist has never hidden his desire to re-sign the 34-year-old, who has trained at Murray Park on several occasions during breaks from Canada.
Whitecaps head coach Carl Robinson told the club's official website: "We are thankful for the contributions Kenny made both on and off the pitch during his time in Vancouver.
"He has been a great role model, a constant professional, and someone who I consider a very good friend. We wish him and his family all the best."
Miller joined Whitecaps in June 2012 and scored 13 goals in 45 appearances.