Leinster full-back Girvan Dempsey sustained a shoulder injury during Friday's 25-3 defeat to France and has lost his fitness battle.
It is a dramatic return for Murphy, who was controversially omitted from the 22 against France, as Ireland launch their last-ditch effort to qualify for the quarter-finals.
In the second change, Denis Hickie replaces Andrew Trimble on the left wing with the Ulster player paying the price for his defensive frailties against the hosts.
Trimble displaces Gavin Duffy on the bench with Hickie playing probably his last match following his decision to retire from all rugby after the World Cup.
Ireland coach Eddie O'Sullivan has left the hooker slot open as he waits for injury updates on Jerry Flannery (shoulder stinger) and Rory Best (dislocated thumb).
Both front rows could be available for the Pool D finale at Parc des Princes and O'Sullivan will make a final decision over who starts in the next couple of days.