Blackwell said: "The present arrangement is not ideal for Steve and Craig. When I think they are good enough I will sign them. They are desperate to stay at the club because they have no stability at the moment."
Chris Bart-Williams is still on trial but Blackwell has not yet decided whether to make him an offer.
But the manager may switch his attention to West Brom's Sean Gregan if he can persuade the Leeds board to fund another cash signing following Stephen Crainey's arrival at the club.
Gregan has requested a move away from West Bromwich Albion. He has been a prominent figure at The Hawthorns since his move from Preston but new arrivals in the summer mean he is no longer in Gary Megson's plans.
Leeds have emerged as the favourites to sign the midfielder although Cardiff are also interested.
Much will depend on the transfer fee demanded by West Brom.