Boss Billy Dearden admitted on Saturday that Allsopp could make it back for the final few games of the season, but at the moment that is touch and go.
The Aussie has 11 goals so far this season, 7 behind Notts' leading scorer Mark Stallard, who is now destined for finish top scorer for the 3rd time in 4 seasons.
With Allsopp being injured, any chance of a move to Luton Town looks dead and buried for the moment. Hatters boss Joe Kinnear was interesting in signing Allsopp from The Magpies and had spoken to his agent, but any possible deal is now almost certainly dead.