McFarland said: "Some of the trialists are still with other football clubs. So it would not be right to to say who they are.
"More importantly, I do not wish to tip off other clubs who we are looking at as finding, and then signing, quality players has now become a very competitive business.
"We are between a rock and a hard place on this. If we keep our supporters fully informed and then lose out, we get criticised for showing our hand, and if we don't say anything our supporters think nothing is happening."