The decision taken by Monty Panesar and Chris Tremlett to switch counties last year has been the catalyst for their England recalls, according to national selector Geoff Miller.
The pair were named in England's 16-man Ashes party to defend the urn Down Under this winter after stellar domestic campaigns.
Left-arm spinner Panesar, who played the most recent of his 39 Tests 14 months ago, took 52 Championship wickets for Sussex after joining from Northamptonshire.
Paceman Tremlett picked up 48 Championship scalps for Surrey after arriving from Hampshire looking to revive a career that had stalled since he played three Tests in 2007.
"They have something in common, they have both been playing for new clubs," noted Miller.
"We have watched them both constantly. Chris Tremlett has led the attack at Surrey, as opposed to just being an ordinary bowler at Hampshire.
"He's taken the responsibility and he's bowled really well. Conditions in Australia should suit him."
On Panesar, he added: "Monty went away and developed his game.
"He was having a bad time - he appreciated that and we appreciated that.
"We told him what he needed to do. He's got a new area (county) to play for and has produced the goods - so now we have two quality spinners going over.
"...I think he has developed as a person. There were times when you thought he wasn't thinking for himself - and I think that's changed.
"He's been given the onus to do that at Sussex and has responded.
"He has bowled really well, has set his own fields, has had conversations with the captain and coach - and has developed as a player and a person."
The main omission from the Ashes squad was Yorkshire seam bowler Ajmal Shahzad, who was overlooked in favour of county colleague Tim Bresnan.
"He was disappointed to miss out," Miller said of Shahzad.
"There are areas he wasn't quite right on and needs to develop.
"It was a difficult decision but Tim got the nod and Ajmal will be in the Performance Programme squad - which helps us."
Another Yorkshireman, Adil Rashid, did not even make the Performance Programme squad, a decision Miller explained by claiming the leg-spinner needed a rest after a season in which he collected 57 wickets in Division One of the LV County Championship - the most by a spinner.
"Adil has been around with us for a couple of years now," said Miller. "And, as he hasn't made the squad, it is a necessity for him to have a break.
"He will be having a break from bowling and we will re-assess him after Christmas ahead of the Lions' tour.
"It has been discussed with him and the decision was taken between us, himself and Yorkshire - they were involved in the conversation with Martyn Moxon - and we think we've made the right decision."
Meanwhile, Miller also confirmed that batsman Ravi Bopara was not included in either squad as he will play first-class cricket in South Africa this winter.