Johnstone believes that Rangers are going to have a major squad clear out this summer.
Speaking to the Evening Times, club legend Johnstone has admitted that he thinks the majority of Rangers' out-of-contract players are set to be released this summer, although people could still earn new deals.
The former striker said: “What happens in the play-offs will determine who stays and who is released. The fact that players will be trying to earn themselves a new contract could be useful in the play-off matches. They will be trying to impress the manager.
“But I would think the vast majority of the 11 players who are out of contract will be moved on.”
This added motivation to earn new contracts could be the difference maker in Rangers looking to win promotion to the Premiership, as players put in all their effort to impress Stuart McCall ahead of next season.
A number of players are out of contract, and Johnstone expects many to leave at the end of their deals, even if promotion is won, but that could be a risky move.
The club would have a decimated squad if releasing every player out of contract, and that would require major rebuilding ahead of a potential Premiership season.
Obviously, there are players in that squad that are nowhere near good enough for the top flight, having struggled to impress in the Championship, but as squad options they are useful.
If removing every single player at the end of their deals, McCall - who himself is still not assured of a career at Ibrox next term - would have to rebuild a squad between the end of the play-offs and the start of next season.
That is a task that would be hard for any club, but is made especially hard due to the limited finances possessed by the Light Blues.
The club might not want to keep a selection of their players, but it is hard to deny that many may be needed next term regardless.