The 29-year-old batsman has already played in the Global T20 Canada League since being handed a 12-month ban from international and state cricket for his part in the ball-tampering scandal that rocked the game earlier this year.
Still the number one ranked test batsman in the world, Smith replaces Shakib in the Barbados Tridents side after the Bangladeshi all-rounder became "unavailable" for the tournament, organisers said.
"It is a huge blow to lose Shakib for the tournament but in Steve Smith we have a truly world-class replacement who can help to bring power to our batting line-up," Tridents coach Robin Singh said in a news release.
"As a man who has played cricket at the highest level all over the world, we are very confident that Smith will be a big success with the Tridents."
David Warner, Smith's former vice captain who is serving a similar 12-month ban for his role in the scandal, will also be turning out in the CPL having replaced D'Arcy Short at the St Lucia Stars when the all-rounder was called up by Australia 'A'.
(Reporting by Nick Mulvenney, editing by Amlan Chakraborty)
