Rahul Dravid, Sourav Ganguly, Yuvraj Singh and Gautam Gambhir are among the big names released by their IPL franchises, along with Brendon McCullum, Chris Gayle and Andrew Symonds, while Virat Kohli is the surprise retention for his team for the next three seasons. Wednesday was the deadline for the franchises to name the players they would retain from their current squads and while there is no common thread running through the choices of players retained and released, the key factors seem to be form, brand appeal and age.

Kolkata Knight Riders, Deccan Chargers and Kings XI Punjab have decided not to retain any of their players, while all the other IPL franchises have held back at least one current player. Chennai Super Kings and Mumbai Indians, the 2010 finalists, have retained the maximum of four players each, in the process parting with half of the $9 million salary cap available to teams.

According to the auction rules for IPL 4, teams can retain up to four players, only three of whom can be Indians. The retained players - who must have been part of the franchise's registered squads for the 2010 season - will be valued at $1.8 million for the first player, $1.3 million for the second, $900,000 for the third and $500,000 for the fourth.

Mumbai, as expected, held on to Sachin Tendulkar, the highest run-scorer of the 2010 season, offspinner Harbhajan Singh, West Indies allrounder Kieron Pollard and Sri Lanka seamer Lasith Malinga. Chennai took the Indian trio of MS Dhoni, Suresh Raina and M Vijay out of the auction, in addition to South African allrounder Albie Morkel, their regular opening bowler. Delhi Daredevils retained only Virender Sehwag, meaning Gambhir - their captain for the last two seasons - is in the auction pool.

The retained players Mumbai: Sachin Tendulkar, Harbhajan Singh, Kieron Pollard, Lasith Malinga Chennai: MS Dhoni, Suresh Raina, M Vijay, Albie Morkel Rajasthan: Shane Warne, Shane Watson Delhi: Virender Sehwag Bangalore: Virat Kohli

The most interesting choice came from Royal Challengers Bangalore whose sole retention is Virat Kohli, currently on an impressive run in ODIs. There is no place for Dravid, their icon player, nor for Anil Kumble, their captain and the head of the state association. Kolkata's decision to drop Sourav Ganguly, the biggest cricketing name to emerge from the city and the face of the franchise's on-field persona, is a bold step.

Punjab's decision to release all their players was expected following their dismal 2010 season, which means Kumar Sangakkara, Mahela Jayawardene and Yuvraj Singh will go under the hammer.

Siddhartha Mallya, owner of the Bangalore franchise, said the decision to retain just one player was backed by financial logic. "You must realise that with retention, a big chunk of your budget gets taken away," Mallya told ESPNcricinfo. " Mumbai and Chennai have kept four players, which means that half their budget is gone. It finally comes down to how much money one was going to lose. We have a big balance sheet but we have lost $1.8 million for keeping one player. We still have about $7-odd million left but if we had retained four then we would have had to buy virtually an entire squad with the remaining half."

Age is not a universal disqualification. It didn't count in Tendulkar's case, nor in that of Shane Warne, Rajasthan's coach and captain, who was retained by Rajasthan Royals, along with Shane Watson, a day ahead of the deadline. One franchise official explained the difference: "Warne is a global brand so that only helps to promote the franchise."

If Rajasthan opted for Warne because they have always viewed the IPL as a global brand, Mumbai went with Tendulkar and Harbhajan for their popularity. Pollard and Malinga may have made the cut on account of being impact players, who have backed up their strong Twenty20 credentials with consistent performance.

Sehwag's match-winning abilities, coupled with his rapid emergence as a brand, clearly had a say in Delhi's decision to retain him. MS Dhoni and Suresh Raina must have been shoo-ins for Chennai following their compelling IPL and international form. Vijay's performances, coupled with his potential to attract a strong local fan-base, must have tilted the scales in his favour, while Morkel's proven all-round skills were always going to be an asset. If there is a stranger in this crowd, it could be Kohli. Despite his owners trumpeting his recent performances, Kohli is still work in progress. But he is young, ambitious and has the youth appeal - all qualities of the UB Group's target audience.

With inputs from Nagraj Gollapudi