Lockwood has been sidelined since late September after breaking two bones in his foot, missing Rovers' last six matches, while fellow central defender Shackell sat out the 2-1 defeat at Plymouth last time out due to a groin injury.Shackell, on loan from Wolves, had an injection in his groin last Friday and has targeted a return to full training on Thursday.A third centre-half, Byron Webster, could also return against QPR.Webster dislocated his elbow in last month's draw at Sheffield United in October and has missed the last five matches.
Source: Team_Talk