Donal Lenihan believes Andy Farrell's greater first-hand familiarity with Conor Murray dictated the Ireland head coach's decision to select the Munster scrum-half over John Cooney for the Six Nations opener against Scotland.

In the lead-up to Tuesday's team announcement, many had called for Ulster's in-form Cooney to get the nod to start.

But Farrell has instead gone for the international experience of Murray, with Cooney as a bench option.

Speaking on RTÉ Radio's Morning Ireland, ex-Munster and Ireland man Lenihan assessed Farrell's decision on the scrum-half position.

He feels it is down to more time working with Murray and the fact that Farrell has not had the benefit of warm-up matches.

"That was the one that everybody was looking at to see if this is going to herald the new era and how far is Andy Farrell going to go," he said of the Murray-Cooney call.

"But to be honest with you, I always thought he was going to start Conor Murray.

"Andy Farrell, unlike his predecessors Declan Kidney and Joe Schmidt, doesn't have the luxury of a November series or a summer tour to start tinkering with his team.

"He's straight in at the business end of Six Nations. He's had Conor Murray on two Lions tours. He's had him as part of his defensive set-up for the last four years.

"I think he's seen a spark in Conor Murray over the past number of weeks.

"He hasn't played well now for almost 12 months, but there are signs that he is coming back to his form.

"I think he's offering Conor Murray a chance to play himself into the international form that we all know he's capable of.

"But I think John Cooney on the bench, he was there last year during the Six Nations and he only got bit-parts, whereas now I see Cooney coming in with 20 minutes to go, looking to put his particular stamp on the game.

 Caelan Doris during Ireland Rugby squad training at The Campus in Quinta da Lago, Portugal

"I wouldn't be surprised if Cooney gets his opportunity further down the line in the Six Nations." 

Lenihan added that any "big changes" for Ireland are unlikely to come until after the tournament when the team goes on tour to Australia.

While Farrell has stuck with Murray, he has made five changes to the team that lost heavily to New Zealand at the Rugby World Cup.

"More interestingly for me, there are only two changes to the side that played in the opening game against Scotland in Yokohama in the vital pool game which Ireland won pretty decisively," said Lenihan.

"The back three that day - Jordan Larmour, Andrew Conway and Jacob Stockdale - they're reunited which is interesting.

"There was a clamour for them to be kept in the side for the quarter-final. It didn't happen.

"I think that's a very interesting back three.

"Overall, Caelan Doris, I'm delighted to see him in the side. He's been the standout of the younger players in the season so far.

"I watched him playing for Ireland at Under-20s level. He's an outstanding player who's got better and better with the opportunities that Leinster have afforded him in the Champions Cup this year."

Follow Ireland v Scotland (kick-off 4.45pm) on Saturday via our live blog on RTE.ie/Sport and the News Now app or listen live on RTÉ Radio 1's Saturday Sport. Highlights on Against the Head, Monday at 8pm on RTÉ2 and RTÉ Player.