On Friday, England are set to name an expanded squad of 19 for the seven matches in Pakistan and the T20 World Cup (that will have 15 players plus three reserves) that follows.
It is not set to include Jason Roy, but does contain his Surrey and Oval Invincibles opening partner Jacks, plus Kent and Invincibles batter Jordan Cox for the Pakistan leg.
Seamer Helm has won a place in the squad on the back of some impressive performances for Birmingham Phoenix in the Hundred and Middlesex earlier this year.
Jacks and Helm were both unused members of the squad for an ODI series against Pakistan last year when England’s first-choice players were struck down by Covid, but are yet to be capped.
It seems unlikely that there will be a place for Will Smeed, the Somerset starlet and scorer of the Hundred’s first century with Phoenix, has not received a maiden call-up, while there is also no recall for James Vince.
England have multiple injury doubts, including to captain Jos Buttler, who will travel to Pakistan but is likely to be ruled out of the early part of the series due to injury.
Liam Livingstone and Chris Jordan are among the other T20 players ruled out of the Hundred early with injury.
Mark Wood is set to be available after injury, but England are still without a host of other fast bowlers, including Jofra Archer.