Lawless and Williams unavailable for the TownTown boss John Still will be without Luke Wilkinson, Alex Lawless and Curtley Williams for Saturday's game with Mansfield Town at Kenilworth Road.
The Hatters aim to bounce back to winning ways in League 2 after losing 1-0 at Burton last weekend, but the manager revealed at his Thursday press conference that midfielder Lawless has chipped a bone in his foot and could out for up to three weeks.
Defender Williams dislocated his shoulder for the second time this season during Tuesday's development squad fixture with Leyton Orient on Tuesday. He joins Lawless and striker Ross Lafayette on the sidelines.
Centre-half Wilkinson, meanwhile, serves a one-match suspension after his red card in the final minute at Burton last Saturday.
Pelly Ruddock Mpanzu is expected to resume training on Friday after missing the Thursday session, but Still did have good news to report in that leading goalscorer Mark Cullen has returned to full training this week.