Hip and hernia problems have dogged the Warwickshire left-armer, a key member of England's Ashes-winning side last year, in recent times and he has ruled himself out of the three-Test series starting against Sri Lanka at Lord's on Thursday.
But he hopes to be ready for the first Test against Pakistan, the second team touring England this year, which starts at Lord's on July 13.
"We think we have got to the bottom of my problems. It seems to be a dodgy groin," Giles told a reception at the Houses of Parliament to officially launch this summer's international cricket programme.
The 33-year-old said his injury has been diagnosed as "a Gilmour groin - a type of hernia."
He added: "I've had the hip problem and the hip problem is still there. Which came first - the groin or the hip?
"One could have had an effect on the other. But hopefully we've got to the bottom of it and hopefully in five weeks I can start playing cricket."
Meanwhile, with England facing a packed schedule in the run-up to the defence of the Ashes in Australia, Giles said it was vital everything was done to keep key players, such as all-rounder and stand-in captain Andrew Flintoff, fully fit.
"We have to keep the key players fit," said Giles, who is currently joined on the sidelines by injured captain Michael Vaughan and the crocked pace trio of Stephen Harmison, Simon Jones and James Anderson.
"It puts more pressure on the senior guys still in the side. The one we are talking about is Andrew Flintoff. You can't be losing Andrew Flintoff coming into the Ashes. He's that much of a good player but it's a difficult balance."
England's chairman of selectors, David Graveney, said it was important that new players were bedded in before the Ashes.
"We see some of the young guys like Alistair Cook who we think will be playing a part in Australia. We need to give him as much experience as we possibly can.
"We have some fantastic depth. Now our job is difficult for the right reasons, that we have lots of people to select from.
"I mentioned the word rotation some months ago and we have to deliver our guys physically fit to play Australia because that's what the cricketing public deserve," Graveney added.
Looking ahead to the Sri Lanka series, Giles said: "Over here you are looking to dominate with your quick bowlers.
"Sri Lanka are not used to playing the ball at chest height, particularly against somebody quick like Andrew Flintoff."
But he warned that star Sri Lanka off-spinner Muttiah Muralitharan would be a threat in all conditions.
"Murali's going to be a handful. It might be his last trip to England. We all love to see him bowl and hope he has a relative amount of success - but that England win three-nil."