Sky Sports understands that Ian Black and Craig Beattie are training with Rangers newco, while Gary Teale is also destined for Ibrox.
Black and Beattie find themselves without a club following their release by Hearts.
Black agreed to join the Gers in early July, but has been waiting for the Glasgow giants to obtain a Scottish FA membership.
The Gers are still waiting on that licence, but have added Black and Beattie to their pre-season training programme.
Ally McCoist is, however, blocked from offering them a contract until the Gers' place in the Scottish Third Division has been officially confirmed.
Once the relevant paperwork has been completed, it is understood that Rangers will also look to draft Teale into their ranks.
The former Wigan, Derby and Sheffield Wednesday winger is currently on the books of St Mirren, but it is understood that transfer talks have already been held.