Warner will replace fellow Australian, D'Arcy Short, who is no longer available for the tournament due to being selected for Australia A's tour of India which takes place in August and September.
Stars general manager Mohammad Khan said: "We are excited to bring David to the Saint Lucia Stars".
Warner and Smith were handed with 12-month suspensions by Cricket Australia for their involvement in ball-tampering during the third Test in Cape Town during their four-match tour of South Africa, while Bancroft was given a reduced nine-month sentence.
The reproduction of the story/photograph in any form will be liable for legal action. "He is going to add a lot of value on the field and in the dressing room as we pursue our first title", ESPNcricinfo quoted Warner, as saying.More news: Caracas Nightclub Stampede Leaves 17 Dead
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Warner is now serving a one-year ban - along with Steve Smith, who was also stripped of the captaincy - for his part in the scandal in South Africa, while Bancroft is suspended for nine months. He has confirmed his participation in other cricket leagues such as Global T20 league Canada and Northern Territory strike league in Darwin.
This was Warner's first game in two months and the 31-year-old played some eye-catching shots, which left several spectators in awe of him.
This year's CPL will be held from August 8 to Sep. 16.