Pietersen returned to the England side in all forms of the game last winter in India, suggesting a new approach after the problems which had blighted his relationship with Strauss, who believes his former team-mate's interest in the Indian Premier League was at the root of all the problems.
"His 'falling out' with the team in the South Africa series was brought about by his interest in the IPL, a tournament tailor-made for his talents and personality, and by him losing his love for the England cricketing environment," Strauss said.
"He has never been one to bottle things up. That he lashed out, by sending text messages to the opposition, and by distancing himself from his team-mates, is something that he probably regrets.
"Important lessons have been learnt over the past 12 months, by Pietersen, the ECB and his team-mates. It is to his great credit, as well as the rest of the team, that they have been able to move forward from the trials of last summer so adeptly.
"A fully fit, motivated and focused Kevin Pietersen is an immense asset to any side. If he intends to prove his commitment to English cricket over the next six months, then Australia had better look out."
As a three-time urn winner as a player and a two-time victor as a captain, Strauss knows better than most about the pressures of facing the Baggy Green, as well as the complexities of leading individuals such as Pietersen.
"He knows as well as anyone that reputations can be forged and destroyed in those seven weeks," Strauss said. "Alongside his outrageous innings at The Oval in 2005, his performances in Adelaide in 2006 and 2010 stand out.
"In Ashes Tests he averages 52.7 - more than three runs better than his overall average. If England find themselves seeking inspiration this summer, expect him to deliver."