It will also be the Kildare man's first Test start since the Six Nations defeat to England at Twickenham last March and it is an opportunity he intends to grasp with both hands.
"It's always frustrating (not being in the team) because every player wants to be in the team and every player believes, in their own mind, that they're good enough to start," he said.
"Not being arrogant, but I think every player will tell you that. It's always frustraing for a guy when he's not in the team.
"For me, I've had a few injuries, bits and pieces. I was lucky enough to play a good bit of the Six Nations last season and I've been there or thereabouts.
"I'm looking forward to facing Argentina now and just trying to play my game."
Murphy has good experience of playing the Pumas - he has lined out for Ireland against them on four previous occasions and also played against them for the British & Irish Lions in 2005.
He was capped twice on Ireland's 2007 summer tour to Argentina and scored his 18th Test try in the 2007 Rugby World Cup pool defeat to the Pumas, which was the sides' last meeting.
"Argentina are a very proud nation, it's always a very physical game against them. Now they've got some skilful backs and very quick and elusive backs," Murphy added.
"They're a complete side. They're ranked fourth in the world and they haven't got there by accident.
"They're a strong team and it's going to be a very difficult game for us at the weekend."
Murphy is expecting a very thorough test under the high ball on Saturday as having worked with Marcelo Loffreda at Leicester last season, he knows how much emphasis Argentina can put on the kicking game.
"I was coached by an Argentinian coach last season and it was certainly one of the principles that he worked very hard on and that I worked very hard on underneath him.
"I'm sure it will be raining from a great height and hopefully it will go well for us at the weekend."
Murphy's selection at full-back was endorsed by Ireland coach Declan Kidney at the team announcement press conference.
"Geordan's been playing well. Full-back is just one of several areas that's highly competitive at the moment," Kidney said.
"It was tight over the last few weekends as to who we would start, so we just felt he would be the right man for the job this Saturday.
"He's a good reader of the game, he's a good team person, a good pro. Like all players, he has strengths. He has the odd few things that mightn't go his way, but every player is like that.
"He has been around that long that you all know what he's good at and what he brings to the team and I believe that's going to be important on Saturday."