Tuqiri has undergone scans confirming a fracture to his right forearm, while Lawrence has been discharged from hospital after dislocating his hip.
The pair are expected to be out of action for two and three months respectively.
The injuries marred an otherwise successful outing against the Raiders, which saw the Tigers run in six tries in a 34-24 victory.
The news is also hammer blow to Tigers coach Tim Sheens’ premiership aspirations.
Lawrence, who recently signed a five-year deal with the club, is set to undergo further tests on Monday.