What the numbers tell us about the IPL's most valuable players

Ahead of the big IPL auction this weekend, we trawled through ESPNcricinfo's ball-by-ball data from the past five editions of the tournament to profile players under the various key skill categories in T20s. Top-order batsmen with an ability to offer quick runs on a consistent basis, dependable finishers who can be banked on to see teams through the death, and bowlers who have been most effective at stopping batsmen from doing so. Here are the results, which offer a flavour of what franchises would be looking for when 578 players go under the hammer on Saturday.

The must-have top-order bats
The first six overs of a T20 game are when teams look to set the perfect launchpad to achieve an above-par score. Equally, chasing sides look to exploit fielding restrictions and try to ensure they don't fluff up their pursuit of the target. A good start invariably results in a good score and teams would look for players that maximise the runs (Average runs scored in PP) as quickly as possible (Strike Rate). Players who do this on a consistent basis are likely to be value buys. The proven players seen in the "Must-Haves" quadrant in the league are David Warner, Rohit Sharma, Suresh Raina and Jos Buttler, most of whom have already been retained by their franchises, while some other highly reputed players start off relatively slowly and make up towards the latter half of the innings. Ideally, teams would look to pick a good mix of players from the Must-Haves and some from the Slow Starters to ensure a balanced approach. The likes of Saha, McCullum and Mandeep score quickly but don't carry on while Chris Gayle, Lendl Simmons and Ajinkya Rahane do a bit of both.

What do the best finishers do right?
The final five overs at the other end of the innings is when teams go hell for leather in their pursuit to set a tall target or chase one down. In this phase, teams would look for players who can minimise the number of dot balls (Dot ball %) and also score boundaries as frequently (Balls per Boundary) as possible. Rohit Sharma, AB de Villiers and Virat Kohli - again, players held in high regard and retained by their franchises - are ideal for teams to have in that situation, but it is hard to expect them to bat through the innings all the time. Chris Morris, Suryakumar Yadav and David Miller are other names who have proven to be ideal finishers from time to time. The likes of Chris Gayle, MS Dhoni and Andre Russell and Hardik Pandya are all great boundary-hitters but have been known to play a few too many dot balls in recent IPL seasons. Another interesting set of players are Ravindra Jadeja, Axar Patel and Deepak Hooda who look to score off as many balls as possible but don't have the ability to clear the fence at will.

The ideal tweakers
The value of wristspinners and mystery spinners is now all too well known across the T20 world, and two of the very best, Sunil Narine (retained by Kolkata Knight Riders) and Rashid Khan (Sunrisers Hyderabad), stand out in our analysis. Spinners who pick up wickets frequently (Strike Rate), while keeping the runs down (Economy Rate) are a rare commodity in a format where batsmen have the license to go for the big hits every other ball. Among Indian spinners, Axar Patel stands out, while a number of offspinners like R Ashwin and Harbhajan Singh fall in the Control Bowlers category, which covers bowlers who pick up wickets less frequently, while keeping the runs down. A few other wristspinners like Imran Tahir, Kuldeep Yadav and Yuzvendra Chahal comprise the Strike Bowlers, involving more expensive bowlers who have a tendency to pick up wickets regularly and break partnerships. As with all other categories, franchises would do well to acquire a mix of control and strike bowlers.

What makes a great death bowler?
Apart from the fact that you have to execute good yorkers and deceptive variations, it is important to reduce the flow of runs (Economy Rate) and take wickets (Strike Rate). Three of the best in this category - Andrew Tye, Jaydev Unadkat and Dwayne Bravo - have been covered on these pages earlier. Bhuvneshwar Kumar, Mitchell Starc and Lasith Malinga are proven death bowlers and it is not a surprise they are up there with the best numbers over the past five years. However, the most interesting case is that of Jasprit Bumrah, who has a poor Strike Rate, but a healthy Economy rate. One reason could be that batsmen are looking to just play him out without losing their wicket.  So ideally, having retained Bumrah, Mumbai Indians should look to add strike bowlers to complement Bumrah. Umesh Yadav, Sandeep Sharma and Jaydev Unadkat fall under this category, taking a lot of wickets but leaking heavy runs.