They never lasted long but Dan Carter admits dark thoughts infiltrated his mind, telling him he would never play for he All Blacks again.

Universally regarded as a Test rugby great, Carter makes his long-anticipated starting return at first five-eighth against Scotland at Murrayfield on Saturday.

The 32-year-old admits his mounting physical woes left him occasionally wondering if someone was trying to tell him something.

“There’s all sorts of doubts with your body when you have injuries like I have. That creeps in,” he said.

“Maybe in darker times you question whether you’ll get the chance to pull the jersey on again.

“It’s normally straight after an injury but you soon get out of that hole.”

It is nearly a year since Carter’s last Test start, injuring himself early against England at Twickenham before beginning a six-month break.

His return wasn’t the smooth path envisaged, fracturing his leg in the Super Rugby final and enduring three frustrating months of recuperation, which put his involvement in this tour in doubt until the last minute.

An encouraging half-hour off the bench against the United States in Chicago lifted Carter to 365 minutes of rugby this year.

More importantly, it boosted his confidence ahead of more formidable Tests, stating that he is pursuing a place in the team to face Wales in Cardiff next week.

That means he can’t be satisfied to merely get through Saturday’s Test unscathed.

“Every time I pull on the black jersey I want to be one of the best players out there, if not the best.

“But I still have to be realistic about my lack of preparation up to now.”

Carter says he has enjoyed hitting full capacity with both his running and goalkicking at training this week.

While teammates may start to be concerned about fatigue, he says he feels like he has boundless energy.

Carter is buoyed by his last appearance at Murrayfield, two years ago when he ran brilliantly and kicked 21 points in their 51-22 drubbing of the Scots.

He feels like he is in the same boat as many of his inexperienced teammates, who have points to prove with next year’s World Cup in mind.

“It’s a huge opportunity for every player to stamp their mark and perform well.

“Getting to the end of the season, there are a couple more opportunities, and next year is obviously a huge one for me.”