Leinster's head coach Leo Cullen is able to call upon returning Ireland squad members Michael Bent, Jack Conan, Fergus McFadden, Noel Reid and Isaac Boss for Friday night's opening Guinness Pro12 match against Edinburgh in Meggetland (7.35, live on TG4).
Former St Michael’s College team-mates Luke McGrath and Cathal Marsh form the halfback partnership; the school contributes two other players in the starting team, centre Noel Reid and flanker Dan Leavy, and three on the bench, Royce Burke Flynn, Ross Molony and Ross Byrne for a total of seven.
Kevin McLaughlin captains the side from blindside flanker for his 115th appearance in blue after an injury disrupted season last year where he only played five times. His last competitive appearance was against Connacht in December.
On the replacements bench one of Burke-Flynn, Byrne or Garry Ringrose will become Leinster player number 1235 if they make an appearance off the bench as all three are in line to make their debut in Meggetland.
Andrew Trimble will win his 189th cap for Ulster against the Ospreys at Kingspan Stadium on Friday night (7.35, live on BBC2), hoping to improve upon his tally as the province's record try scorer.
The game will also see Peter Nelson start his first game for Ulster at outhalf. The versatile 22 year old, who has previously played 10 for Dungannon RFC and Ulster A, returns to the position following injuries to Ian Humphreys (hamstring strain) and Sam Windsor (Achilles). Head Coach, Neil Doak, has selected six forwards and two backs on the replacements bench with John Andrew, Ricky Lutton, Bronson Ross, Peter Browne, Clive Ross and Sean Reidy named alongside David Shanahan and Sam Arnold.
Meanwhile Connacht coach Pat Lam will give a Pro12 debut to Academy centre Rory Parata against the Newport Gwent Dragons on Friday night at the Sportsground (7.30) after he started in two pre-season games against Castres and Munster. Bundee Aki will partner the 21-year-old in midfield.
Up front new flanker Nepia Fox-Matamua earns his first cap in a Connacht jersey starting in a backrow with captain John Muldoon and number eight Eoghan Masterson. Former Leinster lock Ben Marshall is likely to be sprung from the bench for his first official Connacht appearance.
Leinster: I Nacewa; F McFadden, B Te'o, N Reid, D Fanning; C Marsh, L McGrath; M Bent, A Dundon, J Hagan; T Denton, M McCarthy; K McLaughlin (capt), D Leavy, J Conan. Replacements: B Byrne, P Dooley, R Burke-Flynn, R Molony, D Ryan, I Boss, R Byrne, G Ringrose.
Ulster: L Ludik; A Trimble, L Marshall, S McCloskey, C Gilroy; P Nelson, P Marshall; A Warwick, R Herring (capt), W Herbst; D Tuohy, F Van der Merwe; R Wilson, W Faloon, N Williams. Replacements: J Andrew, R Lutton, B Ross, P Browne, C Ross, S Reidy, D Shanahan, S Arnold.
Connacht: Tiernan O'Halloran; Danie Poolman, Rory Parata, Bundee Aki, Matt Healy; Jack Carty, Kieran Marmion; Denis Buckley, Tom McCartney, Rodney Ah You; Quinn Roux, Andrew Browne; John Muldoon (capt), Nepia Fox-Matamua, Eoghan Masterson. Replacements: Dave Heffernan, JP Cooney, Finlay Bealham, Ben Marshall, Eoin McKeon, John Cooney, Craig Ronaldson, Fionn Car.