'Boots up! Thank you!' - Pietersen calls time on playing career

Kevin Pietersen has had many retirements - including this one in the Big Bash Getty Images

Kevin Pietersen, one of the most brilliant and divisive cricketers of his generation, appears to have called time on his playing career with a four-word update to his 3.65 million Twitter followers.

Pietersen, who had declared in February that this season's Pakistan Super League would be his last tournament, tweeted "BOOTS UP! Thank you!" to his fans in the wake of what seems to have been his final appearance for Quetta Gladiators on Thursday night.

Pietersen's returns in the tournament were underwhelming as Quetta finished fourth in the table to earn themselves a play-off berth - he made 7 from six balls against Islamabad United in that final innings, and managed just one half-century in eight innings all told - albeit an explosive 52 from 34 balls against Karachi Kings.

But now, with the tournament shifting to Pakistan for two Eliminator matches in Lahore before the final in Karachi on March 25, Pietersen has joined his fellow England cricketers, Eoin Morgan, Alex Hales and Jason Roy, in opting out of travelling to the country for security reasons.

At the age of 37, Pietersen's enthusiasm for the hard graft of competitive cricket has been visibly waning in recent months. He warned that he was "nearly done and dusted" during his stint with Melbourne Stars during the Big Bash, and prior to his departure for the PSL, he posted an emotional farewell to his family on Instagram, adding that "this evening is the last one I'll ever have to do."

Pietersen added a further update on his Twitter feed on Saturday morning, which appeared to cement his decision. "Just been told that I scored 30000+ runs which included 152 fifty's & 68 hundreds in my professional career," he wrote. "Time to move on!"

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. He is having a house built near Kruger national park in South Africa, and used two of his final appearances, for Surrey in last season's NatWest Blast and Melbourne Stars in the BBL, to promote the cause with fund-raising "Rhino Days".

Pietersen leaves the sport as England's second highest run-scorer across all forms of the game combined, including 8181 runs in 104 Tests between 2005 and 2013-14, until he was sacked in a dispute over team ethics in the wake of a disastrous 5-0 drubbing in that winter's Ashes.

The acrimony of Pietersen's split with England clouded the final years of his career - not least because the ECB's selectors have, arguably, never yet found an adequate replacement for him in their Test middle order.

But Pietersen's greatest hits will endure long after the bitterness of the latter years has faded. Foremost among the memories will be his unforgettable maiden Test hundred at The Oval in 2005, with which England secured the most absorbing Ashes contest of all time; his Man of the Tournament display in the Caribbean in 2010, when England won the World T20, their first and, to date, only ICC global trophy; and his central role in England's series wins in Australia in 2010-11 and India in 2012-13.

Michael Vaughan, Pietersen's captain during that 2005 Ashes, led the tributes on Twitter. "Well done @KP24 on an fantastic career," he wrote. "Not everyone's Cup of Tea but you will do for me ... Best Batsman I had the pleasure to play with ... 1st England batsman that put fear into the Aussies .. #WellDone"