His side, Quetta Gladiators, have made it to the play-offs of the Twenty20 event, but Pietersen opted out as the remaining matches will be played in Pakistan.
The 37-year-old, who represented Quetta Gladiators during the PSL, has played for a number of teams across the world since 2014, when he was told that he will no longer be a part of England's team. "Best batsman I had the pleasure to play with and the first England batsman that put fear into the Aussies."The England and Wales Cricket Board also posted a message, saying "thank you" to Pietersen.Former England team-mate Andrew Flintoff also congratulated him "on an fantastic career" and thanked him "for having a positive impact on mine too".
Pietersen tweeted: BOOTS UP! I loved entertaining you all!
Pietersen, originally from South Africa, represented England in global cricket.
His latter-day T20 exploits will not detract from 23 hundreds across 104 Test matches, four Ashes wins or 8,181 Test runs.More news: Disgruntled Punjab AAP MLAs to meet Kejriwal on Sunday
"Time to move on", he wrote on Twitter on Saturday.
He tried to revive his Test career, hitting an unbeaten 355 for Surrey, but it was not enough to convince the England and Wales Cricket Board to take him back.
Pietersen, who had a brief and ill-fated spell as England captain, will be best remembered for his sublime innings of 158 in the fifth Test against Australia at The Oval in 2005. He was captain of the team for a short period when the team won 2010 World T20 title.
Though he has shown glimpses of his enduring class in his recent engagements, it is plain that the passion has ebbed away from Pietersen's game - and flowed increasingly into his new love of rhino conservation, for which he is an increasingly committed spokesman. "1st England batsman that put fear into the Aussies", Vaughan tweeted.
Given his often divisive nature, it was fitting that Michael Vaughan, a former England captain, admitted his old worldwide team-mate was a tremendous talent, even if he wasn't always easy to deal with.