Bergamasco, a noted flanker on the international scene, swapped positions and lined out at scrum half in last weekend's 36-11 loss to England.
But the experiment was unsuccessful and with in-form Ireland visiting Rome for round 2, Mallett has made team changes.
Most notably, Josh Sole has made way for the return of Bergamasco to the back row and the New Zealand-born Paul Griffen has been selected at scrum half.
It will be Griffen's first cap since he played against Portugal during the 2007 Rugby World Cup.
He will have his Calvisano team-mate Luke McLean, a former Australian Under-19 international, for company at half-back.
With Andrea Marcato ruled out with a head injury, the 21-year-old McLean, who kicked two penalties as a first half replacement against England, comes in to make his full Six Nations debut.
Tommaso Reato joins Santiago Dellape in the Azzurri's second row, with former captain Marco Bortolami (knee) on the injury list.
Mirco Bergamasco, Mauro's brother, started on the left wing against England but he will be back at inside centre for the Ireland game. Matteo Pratichetti takes the vacant wing berth and Gonzalo Garcia is the player to make way in the reshuffle.
Ulster lock Carlo Del Fava is a familiar face amongst the Italian replacements. Gloucester prop Carlos Nieto is the third English-based player in the matchday 22, along with starting front rowers Fabio Ongaro and Martin Castrogiovanni.
ITALY TEAM & REPLACEMENTS (v Ireland, 2009 RBS 6 Nations Championship, Stadio Flaminio, Sunday, February 15, kick-off 3.30pm local time/2.30pm Irish time):
15 - Andrea Masi (Biarritz Olympique) 45 caps
14 - Kaine Robertson (MPS Viadana) 36
13 - Gonzalo Canale (Clermont Auvergne) 43
12 - Mirco Bergamasco (Stade Francais) 57
11 - Matteo Pratichetti (Cammi Calvisano) 13
10 - Luke McLean (Cammi Calvisano) 4
9 - Paul Griffen (Cammi Calvisano) 38
2 - Fabio Ongaro (Saracens) 60
3 - Martin Castrogiovanni (Leicester Tigers) 55
4 - Santiago Dellape (Toulon) 53
5 - Tommaso Reato (Femi CZ Rovigo) 7
6 - Alessandro Zanni (Cammi Calvisano) 27
7 - Mauro Bergamasco (Stade Francais) 70
8 - Sergio Parisse (Stade Francais) (capt) 58
16 - Carlo Festuccia (Racing Metro Paris) 46
17 - Carlos Nieto (Gloucester) 32
18 - Carlo Del Fava (Ulster) 33
19 - Josh Sole (MPS Viadana) 34
20 - Giulio Toniolatti (AlmavivA UR Capitolina) 2
21 - Gonzalo Garcia (Cammi Calvisano) 6
22 - Andrea Bacchetti (Femi CZ Rovigo) 0