The Sheffield United forward, at Boundary Park on a season-long loan, damaged knee ligaments in pre-season not long after arriving and has yet to kick a ball for Ronnie Moore's side.
"Luke's coming along, but he's got to play reserve-team football yet before we can think about the first team," boss Moore told PA Sport.
"He's only had three days' training after joining us this week and we won't rush him.
"We've got to make sure everything's right and he's happy, but he'll probably play some part for the reserves against Manchester United next Tuesday."