Gallagher, 28 can operate also on the wing and is likely to take the place of suspended Ryan Flynn for the fixtures against Bury (this weekend), Doncaster Rovers and Yeovil Town and may, if he impresses get more games under his belt before returning to the Walkers Stadium.
The one capped Scotland international has found first team opportunities limited so far this season, making just one appearance and has recently attracted the interest from league rivals Huddersfield Town and Ipswich Town but no moves had appeared to take place.
It is believed that Foxes boss Nigel Pearson could allow the striker to leave on a free transfer to free up the wage bill and is seemingly deemed surplus to requirements. In June 2009 it was reported on Blades-Mad that the Blades was lining up a move or Gallagher should any attempt to sign Ched Evans fall through.