Aberdeen have shipped 11 goals in three competitive games this season, with the recent signing of Jerel Ifil failing to prevent Celtic scoring three times in the first half of Saturday's Clydesdale Bank Premier League curtain-raiser at Pittodrie.

Former Parma defender Grassi, a 23-year-old Italian, can play both left-back and centre-half. Ex-Espanyol and Racing Santander man Lopez, a 22-year-old Spaniard, is an option at right-back.