Nottingham Forest's first offer for the player, reported variously as being between £150,000 to £500,000, has been turned down by their League One rivals, despite the fact that 24-year-old Stock is out of contract in the summer.
The Reds have also been linked with Walsall defender Julian Bennett, who has been attracting interest with his displays for the Saddlers this season, as well as Swindon forward Rory Fallon.