Read our preview of all nine teams in the South Group.
Overseas player: Jeetan Patel, Shoaib Malik
The first to take the plunge into city franchise-dom, at least in name only, the Bears have a lot to live up to. Not necessarily in terms of success; their highlight in this format amounts to a sole final in the inaugural competition 11 years ago, but they have lost six quarter-finals since. But on-field failure will be attributed, rightly or wrongly, to rebranding.
Overseas player: Marcus North
With what has happened at the county, the NatWest t20 Blast will be a welcome chance for more expressive cricket and profitable entertainment. A decent run of results would do Derbyshire, and everyone around the club, a world of good. Marcus North joins them on his farewell retirement tour, adding some savviness and class to their batting.
Overseas player: John Hastings (after IPL)
Quarter-finalists last year, Durham were undone by their work with the ball, which explains the signing of John Hastings, who impressed in the Big Bash League earlier this year and will arrive once his IPL stint with the Chennai Super Kings is over. Ben Stokes' participation will be curtailed by England duty, be it selection or ECB prescribed rest. But the frugal recruitment of Irishmen Stuart Poynter and Scotland's Calum MacLoed, who has international hundreds to his name, are smart bits of business.
Overseas player: Junaid Khan
Bringing back Andrew Flintoff perhaps adds a touch of panto to Lancashire's T20 ambitions. Quite how gimmicky it is will be answered by Flintoff's returns - he is already set to miss the first two matches through injury - but the county have always performed solidly if unspectacularly. Their batting lacks a bit of firepower. Although, Freddie's smoking them in the nets…
Overseas player: Ramnaresh Sarwan, Scott Styris
If their Championship performances are anything to go by, the Foxes might be on the verge of bearing fruit as a team. They are littered with young yet established players, most notably their captain Josh Cobb, an exciting white-ball cricketer who possesses the skill and front to excel in high pressure situations. This year, his peers may be able to back him up accordingly.
Overseas player: Richard Levi, Ian Butler
Can they become the first team to defend their trophy? Injury to inspirational captain Alex Wakely is a blow to that aim, but his absence and that of Cameron White (their highest runscorer last season) gives younger players like Ben Duckett and Rob Newton the opportunity to step up. Northants nailed their off-field preparation and on-field execution last year. Expect more of the same.
Overseas player: Peter Siddle
Few line-ups excite quite like Notts - even their video team possess firepower unmatched by others. But away from bowling meteors, this crop of Notts players have struggled to sustain their form in this competition. Last season's YB40 win might have exorcised that demon. Hungry for further success and armed with a host of international-class batsmen, could 2014, finally, be their year?
Overseas player: Mitchell McClenaghan, Colin Munro, Saeed Ajmal
Impressive overseas recruitment pushes the Rapids into "Dark Horses" territory. The powerful left-hander Colin Munro, a great exponent of the reverse sweep, is available for the whole competition, while the world class Saeed Ajmal and Mictchell McClenaghan - who took 17 wickets for Lancashire in last year's competition - will dovetail at the beginning and end, respectively.
Overseas player: Kane Williamson, Aaron Finch (after IPL)
Inexplicably without a T20 trophy to their name, despite the talent at their disposal, the signing of Aaron Finch - the format's No. 1-ranked international batsman - suggests they're addressing that issue. The noise around Headingley is of bumper crowds, extra revenue and, perhaps, Finals Day glory.