Cabinet reshuffle: Cheryl Gillan loses Wales Office
Cheryl Gillan is to be replaced as Welsh secretary in David Cameron's first major reshuffle since forming his government.
Mrs Gillan said on Twitter it had been a privilege to serve in the cabinet but could also serve from the backbenches.
There is pressure from Conservatives in Wales for her successor to be an MP with a Welsh seat.
Possible contenders include Wales Office minister David Jones and Stephen Crabb, a whip.
Mrs Gillan, whose constituency is in Buckinghamshire, had been Welsh secretary since 2010.
On social networking site Twitter, in response to Baroness Warsi's tweet announcing her departure from the UK government, Mrs Gillan said: "Signing off @Welsh_Secretary too but I agree great privilege to serve in cabinet but can serve party from back benches too."
Glyn Davies, Conservative MP for Montgomeryshire and Mrs Gillan's parliamentary private secretary, said he had seen the tweet regarding her reported departure, but knew nothing more.
He told BBC Radio Wales he had been "a huge supporter" of her.
"I must say I've been openly supportive of retaining her in the position," he added.
"There will be a tinge of disappointment with me today because I was a great admirer of Cheryl Gillan's."
Asked if he thought it was the wrong decision, he replied: "It's a matter for the Prime Minister always.
"You can't say what's right and what's wrong. I just think it's right that I should say that I'm a great supporter of hers and I think she did a great job."
As for a replacement, Mr Davies said: "In an ideal world I think a Welsh person, a Welsh speaker, representing a Welsh constituency, I think would be terrific".
However, he said getting the best person for the job was most important, citing the example of New Zealander Warren Gatland as Wales rugby coach.
"If we took that narrow view we wouldn't have Welsh ministers serving in departments where issues are devolved," he added.
"But what really matters is that we have the best person for the job."
Owen Smith, Labour's shadow Welsh secretary, said Mrs Gillan had "worked hard for Wales" and "leaves with her head held high to work on the backbenches".
He said he hoped a Welsh MP would be chosen as her replacement, because "it demonstrates a lack of thought and a lack of care and respect for Wales if we end up with an English MP representing Wales around the cabinet table"
"Even if they have been schooled in Wales - like Maria Miller - they can't have the same degree of understanding and same degree of insight as an MP that represents a Welsh constituency."
Alun Cairns, Conservative MP for the Vale of Glamorgan, tweeted: "As SoS (Secretary of State) she delivered on referendum, electrification of rail & established a Comm (Commission) on Assembly fiscal autonomy".
Former Cardiff North AM Jonathan Morgan, tweeted: "Huge thanks to @CherylGillanMP for all she did as Welsh Secretary & for the support she gave me when I was an AM. Good luck for the future".
Earlier on Tuesday, Grant Tucker, a Welsh Conservative activist, told BBC Radio Wales he felt it was "time for a change".
He said: "There's no denying Cheryl's done a good job and she has stood up for Wales but I think it is time that we need a Welsh MP who's got a Welsh seat."
He added it would "be good to see a 'Welsh' Welsh secretary".
Minister for Disabled People Maria Miller, who was brought up in Bridgend, has also been named as a potential successor.
But there is concern in Welsh Tory ranks that the fact that her constituency of Basingstoke in Hampshire would be a problem.
David Davies, the Conservative MP for Monmouth, said on Monday that appointing another Welsh secretary who represents an English constituency would be "politically very difficult for us on the doorstep to explain" at a time when the Tories hold eight Welsh seats.
Clwyd West MP Mr Jones and Preseli Pembrokeshire's Mr Crabb had earned a place in the cabinet, he told BBC Radio Wales.
Mr Jones was elected in 2005, having previously been an AM from 2002 to 2003. He was appointed parliamentary under secretary of state at the Wales Office after being re-elected in 2010.
Mr Crabb has held the Preseli Pembrokeshire seat, where he grew up, since 2005. He was made an assistant government whip in the coalition with the Liberal Democrats.
Other Welsh Tory sources, speaking anonymously to BBC Wales, said they also wanted a Welsh MP.