Craig Levein insists injuries to key players forced him to pitch Craig Wighton and Sean Clare into action more often than he would have liked.
After an early season run saw the Jambos top the table, the Tynecastle side went seven games without a win after injuries to strikers Steven Naismith and Ikpeazu.
The Hearts boss said: “We tried everything to sign David Vanacek in August but his club were impossible to deal with.
“We had agreed a fee of £50,000, then they changed their mind and said he couldn’t go, then they said they would let him go if they found another striker.
“This went on and on, and I didn’t trust that they would let the deal go through before the window closed. I would have loved to have him in right now to call on.
“But he will be with us on 5 January and will go to Spain and be ready to go. He is an experienced player, 27, and will do the job that Uche did until Uche gets back.
“He will give us that security in the final third and also give us somebody to score from crosses.“In the meantime, we have signed someone I believe is an excellent long-term prospect in young Craig Wighton.
“I think, in time, he will be a very good player. However, what has happened with all the injuries is that, all of a sudden, Wighton has become something I didn’t want him to be: a player we need to rely on during the early part of his time at Tynecastle.”