According to the supersport.com website, Petersen has captained the Lions side for the last three years, during which time they played in the final round of four domestic limited overs competitions and qualified for the Champions League T20 twice.
They reached the final of the 2012 CLT20, losing to the Sydney Sixers.
During Petersen's time at the helm, the Lions' representation at international level increased from one player - Petersen himself - to three nationally contracted players at present, with three players currently on international duty with the Proteas in the T20 format: Chris Morris, Aaron Phangiso and Quinton de Kock.
In addition, the Lions provided the South Africa 'A' team with at least four players.
"When I took over as Lions captain, my immediate focus, together with then coach Dave Nosworthy, was to build a squad who can compete in all three competitions, hence the recruitment of Tsolekile, Bodi, Tahir and Viljoen," Petersen said.
"We have also seen young talented cricketers emerging and also the squad mature as a whole. I do think the squad is complete now, and ready to win silverware. I would like to thank the Lions' board, coaching staff, supporters and most of all the players, for their support and commitment the last three years.
"I wish the new leadership team of Lions cricket all the best, while I look forward to the new challenges and opportunities in my career."
Stephen Cook will captain the side for the remainder of the Sunfoil Series.
"Stephen has set a sterling example as a leader and I believe the best thing for the team at the moment is to have some continuity, said Petersen.
"I have full confidence in Stephen's capability leading the team as we head into the last stretch of the Sunfoil Series."