Nic Maddinson is taking an indefinite break from cricket due to personal reasons and will not feature in this week's Sheffield Shield match.

Maddinson did not play in the NSW Blues' innings victory against Victoria as the Sheffield Shield resumed last week, and no timetable has been set for the 25-year-old's return.

Maddinson was a surprise selection for Australia, alongside 20-year-old opener Matt Renshaw and 25-year-old Victorian Peter Handscomb, as the Test team had an injection of youth following a crushing defeat by South Africa in Hobart last November.

"Cricket Australia and Cricket NSW advises that Australian and NSW batsman Nic Maddinson will not be available for selection due to personal reasons, until further notice," CA and CNSW said in a joint statement before NSW's match with Victoria.

It is understood Maddinson's NSW and Australia teammates have been in touch with the batsman and rallied around him, but his return to playing remains unknown.

Maddinson had the roughest of introductions to Test cricket, facing a rampaging Kagiso Rabada with the swinging pink ball under lights in his debut at Adelaide, bowled for a second-ball duck.

Rabada gives Maddinson a departing spray

He scored 1 and 4 in the Brisbane Test match against Pakistan – also played under lights – and reached his highest score of 22 in the Boxing Day Test.

He was dropped for the third Test against Pakistan, on his home ground at the SCG, with Western Australia allrounder Hilton Cartwright added to the Test XI.

Maddinson returned to the Sydney Sixers in the KFC Big Bash League where form continued to elude him, and he scored 75 runs at 10.71 in seven matches. In his final two games he was bowled by another former Australia batsman in Joe Burns for one in the first over, and run out in the third over of the BBL semi-final, also for 1.

In six Shield innings preceding his Test selection to open the 2016-17 season, Maddinson had scored 235 runs at 39.16, including a brilliant 116 on a turning SCG pitch against Western Australia.

Maddinson marches to Shield century

Maddinson recently reflected on his Test matches and said he "did not feel out of place being in Test cricket".

"I don't know whether I was trying to convince myself I was ready or I actually believed it but I thought I was," Maddinson said.

"Still, you don't know until you're there and have to perform under that pressure.

"At the time I didn't feel out of place being in Test cricket.

"When I was batting I felt comfortable, I wasn't nervous or stressed about being up to the challenge.

"I thought I was adequate and had a few good opportunities to nail down a spot which I missed out so that was disappointing.

"I might not have had the couple of scores in the Shield game before leading up to that Test but I still felt like once I was there I could perform there."

Keep the faith in Maddinson: Clarke

Just a week ago, the powerful left-hander had vowed he would maintain the same mindset as he approached the second-half of the Shield season.

"I'm not going to change anything," Maddinson said last Monday.

"I'm just going to play the same way I was and still have the same mindset as what I did when I was playing those Tests.

"It's more about shot selection at times more so than changing my game and needing a new technique or whatever.

"I'm out there to score runs. If they come at a run-a-ball or come at striking at 30 (runs per 100 balls faced) it doesn't bother me.

"It's pretty cliché to say you want to win games for New South Wales and do well but that's the main goal.

"I want to score hundreds, as many as I can. I don't want to think about Test cricket.

"It is hard (getting dropped) but at the end of the day I've had my chance and couldn't grab so it's back to Shield cricket to score runs again."

NSW are expected to announce a squad for Friday's match against the Queensland Bulls at the SCG on Thursday morning.