Published Friday, 31 January 2014
Andrew Trimble and Isaac Boss during training at Carton House (© Presseye)
Trimble will make his first international appearance since last summer when he won his 50th cap for Ireland against Canada.
His selection comes after Eoin Reddan was ruled out through calf trouble, while Luke Fitzgerald is battling an ongoing hip complaint.
Head coach Joe Schmidt backed the Ulsterman to seize his chance, especially against Scotland's hefty wing duo Sean Maitland and Sean Lamont
"Andrew brings a bit of size, up against Lamont and Maitland," he said.
"We don't have too many men of that size and stature, so Andrew is a good contrast for us."
To be fair to Andrew, he's played very well in the last couple of games, and from that respect he deserves an opportunity.
Head coach Joe Schmidt
Trimble joins Marshall, Best and Henry in the side, while Paddy Jackson and Dan Tuohy are named on the bench.
Henry will make his first start in the competition, while Schmidt says Gordon D'Arcy's stomach bug is the reason behind Marshall's selection.
"Gordon's stomach bug was the sole selection criteria, really," Schmidt said. "Luke Marshall has played really well in the Heineken Cup in big games.
"He played in the Six Nations last year and played very well against Scotland.
"I thought he played well against Australia in the autumn too. He made a defensive error at one stage, but he's learning all the time. He's working hard at everything we're trying to do."
He said of the 22-year-old: "He's between Johnny Sexton and Brian O'Driscoll, so experience-wise, he's a bit inexperienced but either side of him he has two players who can help him navigate his way through the game."
O'Driscoll will earn his 129th cap on Sunday and will become Ireland's most capped player of all time.
Paul O'Connell will captain the side.
© UTV News