Flower took on his role as England's team director in April
England coach Andy Flower will delay announcing England's training squad for the Ashes to give as many players as possible a chance to win a place.
Fringe players such as Ian Bell and Michael Vaughan will now have another opportunity to impress at county level before the list is revealed on Monday.
"The squad we'll initially announce will be larger than the 12 or 13 for the first Test," said Flower.
England's preparations conclude with a match against Warwickshire on 1 July.
England may include Adil Rashid alongside fellow spinners Graeme Swann and Monty Panesar for the extended get-together at the National Performance Centre at Loughborough.
The Yorkshire leg-spinner will be hoping a series of impressive performances in the Twenty20 World Cup will persuade the selectors to afford him an extended stay in the England set-up.
The expectation that the Sophia Gardens pitch in Cardiff where the first Test takes place will take spin will increase his chances of staying on.
Andrew Flintoff, who took six wickets for Lancashire in their 138-run defeat by Durham at the weekend, will be welcomed back for the first time since undergoing knee surgery at the start of the summer.
THE ASHES SERIES
8-12 Jul: 1st Test, Cardiff
16-20 Jul: 2nd Test, Lord's
30 Jul- 3 Aug: 3rd Test, Edgbaston
7-11 Aug: 4th Test, Headingley
20-24 Aug: 5th Test, Oval
"It was very good news to see him back for Lancashire and bowling well," said Flower.
"I think he has another game now, so getting some first-class cricket under his belt is very important for his own readiness for the Ashes. If he's fit he's a shoo-in."
A training camp in Birmingham follows the team's work in Loughborough before a three-day game against the Division Two champions at Edgbaston.
Since defeats to the West Indies and Sri Lanka dumped Australia out of the World Twenty20 at the opening group stage, the tourists have been preparing for the series from their Leicester base.