Pelous, who has 74 caps and captained France 15 times before handing the leadership over to Galthie in 1999, experienced a bad spell in the summer 2001 and missed touring New Zealand and South Africa.
"Fabien has made great efforts to resume at the top level after being sidelined from the 2001 summer tour," said Laporte.
"He is an example for all of us. I think that he came back a better player than before.
"He was also the last France captain before Galthie took charge."
Galthie led France to the Grand Slam last April and is going into his last season after announcing he would retire after the World Cup in October and November.
His injury means 22-year-old Dimitri Yachvili from Biarritz will start in the number nine jersey, while Agen's uncapped Mathieu Barrau comes onto the bench.
"It's always a bad blow to lose your captain and playmaker," Laporte told L'Equipe.
"But it is necessary to remain positive and think that Fabien's absence will at least allow us to see Dimitri.
"The earlier he is thrown into the great international stage, the better it will be for us to evaluate his potential at that level," he said.
Yachvili made his debut with Les Bleus in the 35-3 win over Canada in November and is the son of Michel Yachvili, a former international scrum-half himself.
Barrau also has family ties to Les Bleus, as he is the nephew of Max Barrau, who captained France between 1971 and 1974.