Shaheen and Rauf have made an immediate impression on the tournament, taking five and three wickets respectively in Fire's first three games. Having lost all eight group games last year, Fire have enjoyed a resurgence under new coach Mike Hussey, winning their first game, losing to Southern Brave by two runs and tieing with Oval Invincibles.

The pair are both due to travel to Sri Lanka for Pakistan's three-match ODI series against Afghanistan, with the first fixture on August 22. They are expected to play Fire's next three fixtures before flying, and are therefore set to miss their final two group games on August 20 and 22.

ESPNcricinfo understands that Fire have identified Ferguson and Henry as their replacements and have sent the relevant paperwork to the ECB for confirmation. Ferguson is a like-for-like replacement for Rauf, while Henry will fill a similar role to Shaheen, bowling predominantly with the new ball.

Both players are part of New Zealand's T20I squad for their tour to England which begins immediately after the Hundred, and Henry had already informed NZC that he would be unavailable for the tour to the UAE (August 17-20) in anticipation of a replacement contract. Ferguson is part of the squad for that tour but may now be withdrawn.

Henry has been in excellent form, most recently winning the Vitality Blast with Somerset and finishing the tournament as its leading wicket-taker, with 31 wickets at 13.23. Ferguson has only made two appearances since the IPL, taking three wickets for LA Knight Riders in the inaugural Major League Cricket season last month.