Head coach Joe Schmidt has propelled 22-year-old, four-cap Marshall into his starting line-up, despite D’Arcy’s impressive performance in the 24-22 November defeat to New Zealand.
Marshall has been rewarded for fine club form as Ulster blasted through to the Heineken Cup quarter-finals with a flawless six wins in pool stage action.
Former Ireland and British Lions captain Brian O’Driscoll will win his 129th cap, breaking Ronan O’Gara’s all-time record.
Ireland host Scotland on Sunday before taking on Wales in Dublin just six days later, and Schmidt’s initial midfield selection may well have a strategic element.
The former New Zealand schoolteacher can reasonably be expected to unleash a fresh D’Arcy on the Welsh in round two, after previously admitting the short turnaround between the two fixtures would need careful negotiation.
Marshall will operate as a second playmaker alongside fly-half Johnny Sexton, with Schmidt intent on adding width to Ireland’s attack.
Ulster wing Andrew Trimble starts ahead of Fergus McFadden, winning his first cap since last summer.
Dave Kearney wins his first Six Nations start, alongside older brother and full-back Rob.
Luke Fitzgerald was likely to start but picked up an injury in midweek, while Tommy Bowe and Keith Earls are longer-term casualties.
Chris Henry slots into the back-row for Sean O’Brien as expected, with the Leinster openside out for four months following shoulder surgery.
Lock Dan Tuohy has been given the nod over Iain Henderson on the bench, and Paddy Jackson has been preferred to Ian Madigan as replacement cover for fly-half Johnny Sexton.
Emerging Leinster prop Martin Moore will make his Ireland debut on Sunday after winning a slot on the bench.
The 22-year-old tighthead prop has been named as a replacement for the Scotland clash and will join the fray for the final quarter when Schmidt empties his bench.
Moore and Leinster team-mate Jack McGrath have impressed senior front-rowers in Ireland training this week, notably in scrummaging sessions.
Both will be tasked with adding impetus in the closing stages on Sunday, with Schmidt underlining his high regard for the fast-developing Leinster duo.
Ireland team to face Scotland in the RBS 6 Nations fixture at Aviva Stadium, Dublin, on Sunday:
R Kearney, D Kearney, B O’Driscoll (all Leinster), L Marshall, A Trimble (both Ulster), J Sexton (Racing Metro), C Murray (Munster), C Healy (Leinster), R Best (Ulster), M Ross, D Toner (both Leinster), P O’Connell (capt), P O’Mahony (both Munster), C Henry (Ulster), J Heaslip (Leinster).
Replacements: S Cronin, J McGrath, M Moore (all Leinster), D Tuohy (Ulster), T O’Donnell (Munster), I Boss (Leinster), P Jackson (Ulster), F McFadden (Leinster).