Mike McCarthy is serving a two-week ban, the province's most-capped player Michael Swift is nursing a knee injury and young centre Eoin Griffin is recovering from a hamstring injury.
The front row remains unchanged from the European game with Connacht centurions Brett Wilkinson and Adrian Flavin linking up again with Rodney Ah You.
David Gannon retains his place in the second row and is joined by George Naoupu who replaces the injured Swift in the engine room of the scrum.
The pair played against each other in those positions in the 2004 Under-21 World Championship final, Gannon captaining the Ireland side and Naoupu lining out for New Zealand.
Thomas Anderson, former skipper John Muldoon and Ray Ofisa make up the rest of the pack in a mobile and dynamic back row.
There is a new-look centre combination with Samoan international Henry Fa'afili joining recent debutant David McSharry in the Connacht midfield.
Among the replacements, Elwood can call on the experience of Ethienne Reynecke and Ronan Loughney along with promising prop Stewart Maguire in the front row.
Michael Kearney and Eoghan Grace, who have both shone for Connacht 'A' in recent weeks, complete the forward reserves.
Frank Murphy and Niall O'Connor are the replacement half-backs, while flying winger Mark McCrea covers the outside backs.
CONNACHT (v the Ospreys): Gavin Duffy (capt); Brian Tuohy, David McSharry, Henry Fa'afili, Tiernan O'Halloran; Miah Nikora, Paul O'Donohoe; Brett Wilkinson, Adrian Flavin, Rodney Ah You, David Gannon, George Naoupu, Thomas Anderson, John Muldoon, Ray Ofisa.
Replacements: Ethienne Reynecke, Ronan Loughney, Stewart Maguire, Michael Kearney, Eoghan Grace, Frank Murphy, Niall O'Connor, Mark McCrea.