Half of the quarter-finalists in the Friends Life t20 may be decided this evening in the final round of Friday fixtures.
North Group sides Notts Outlaws and Lancashire Lightning could each qualify tonight, even though the latter are not in action.
Northants Steelbacks have the opportunity to secure their progression from the Midlands/Wales/West Group.
In addition, the winner of the match between South Group rivals Hampshire Royals and Essex Eagles could make it through with time to spare depending on the outcome of Surrey’s encounter with Kent Spitfires.
Derbyshire Falcons, who could yet reach the last eight if other results go their way, hope to welcome back West Indies batsman Shivnarine Chanderpaul for their must-win game with Leicestershire Foxes at Derby.
Chanderpaul, who has scored 182 runs in this year's competition at an average of 45.5, has missed Derbyshire's last three FLt20 matches due to a hamstring injury but, subject to passing a fitness test, will be in the Falcons' squad. His inclusion would in part offset the loss of fellow overseas player Albie Morkel, who has left for the Caribbean Premier League.
Notts take on Yorkshire Vikings, who are already out, at Trent Bridge. Yorkshire are without the injured Joe Sayers and rested Ryan Sidebottom, but have included Jack Brooks, Moin Ashraf, Alex Lees and Will Rhodes into a 13-man squad.
Holders Hampshire must make do without seamer Sohail Tanvir for their next two South Group games after he was called up for Pakistan's two Twenty20 internationals against West Indies.
The first of those is the front-runners' clash with second-placed Essex at the Ageas Bowl today. Wicketkeeper-batsman Adam Wheater has been named in the hosts' squad and could therefore face his former club, while Mark Pettini returns from injury for the Eagles.
Surrey and Kent, who respectively sit third and fifth, will play in front of a sell-out crowd at the Kia Oval.
Midlands/Wales/West Group leaders Northants have named an unchanged squad for a fifth straight FLt20 match for their meeting with nearest challengers Glamorgan at the SWALEC Stadium, where a record county attendance is expected.
Warwickshire Bears, who have an outside chance of progressing and continue to be led by Varun Chopra, have named an unchanged party to take on Worcestershire Royals at Edgbaston.
Gloucestershire Gladiators versus Somerset, one of two tournament games this year at the under-reconstruction Bristol, is sold out.