The reigning Magners League Champions haven't played since the Magners League defeat to Ulster on January 2, while O'Callaghan and a number of other senior figures haven't featured since the historic European win over Perpignan on December 20.
Adverse weather conditions forced the cancellation of their home match against the Scarlets last weekend but O'Callaghan believes the extended time off could work in his side's favour ahead of Saturday's Heineken Cup trip to Benetton Treviso.
"We are fresh after a bit of a break, because it was quite tough with the autumn internationals, which were hugely physical games," O'Callaghan told the Irish Independent.
"Come the end against Perpignan, we were playing with an awful lot of knocks and bangs, but now we are fully recovered, fully refreshed.
"You can see that by your scores in the gym and stuff like that. So, sometimes, a rest can push you on and help you to play a bit better.
"The flip side of it is that you are not match sharp - you can't go as full on as you would like in training, as you can in games - but we know that we are really fresh going into it and that's the positive that I take out of it."
As for Saturday's game itself, O'Callaghan insists Munster won't be taking the Italians lightly.
Treviso shocked French Champions Perpignan in the opening round of pool action before running Northampton incredibly close in their second home match of the competition.
And, having seen Treviso take a shock lead at Thomond Park in the reverse fixture back in October, O'Callaghan knows Munster will not have it all their own way against the group's bottom side.
"You might have thought it was a handy four or five points but we would never disrespect any team by thinking like that," added O'Callaghan.
"I think they have been the best performing Italian team in the competition since it started.
"We know it's a hugely physical game: it always is when we play the Italian teams."
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