Utility back Masi, who plays his club rugby for London Wasps, has amassed 80 caps for the Azzurri, featuring in ten RBS 6 Nations campaigns.
The 32-year-old underwent knee surgery in October but he has now returned to full fitness, completing 80 minutes in each of Wasps' last four league games.
Ideally Masi would like to make his return in the centres at the Aviva Stadium on Saturday, but he conceded Gonzalo Garcia's newfound partnership with Michele Campagnaro may prevent that.
And he is happy to play any role in helping Italy clinch their first win of the 2014 championship - something he knows is a possibility despite a strong Irish outfit.
"There is little to say - I like to play center," said Masi. "But I am happy to play any role in the national team.
"We have all seen how Ireland are doing in the tournament, but also in the past few years Italy has shown in the worst moments the abilityfind the strength to rise again."