Stuart Pearce is said to be open to allowing Blackstock to leave the City Ground on a temporary basis, should the offer be right for both parties, and it seems that his potential availability has alerted a host of teams.
Blades are currently the most interest club of all, but Sheffield Wednesday are also linked and that may be Forest's and Blackstock's preferred choice due to the higher level of football that they can offer.
Forest possess one of the strongest forward lines in the division, meaning Blackstock's chances have been limited.
The 28-year-old has made just one appearance so far this season, after slipping down the pecking order at the Reds, meaning an exit looks imminent.
Blackstock has previously proven to be a good outlet in the second-tier, but the form of Michail Antonio, Matty Fryatt and Britt Assombalonga has blocked his route into the starting line-up.
If he does leave, he will need to show no signs of rustiness though, as the Blades and the Owls have been struggling in front of goal.
The Owls have found goals hard to come by this campaign, scoring just 12 times through their opening 17 league fixtures, and the addition of a front-man has become Stuart Gray's priority.
Nigel Clough, too, has been looking to find a striker who is capable of leading the line at Bramall Lane and, after being blocked in his chase of Chris O'Grady, it seems that Blackstock could be next on his transfer wishlist.