The Three Lions warmed up for their crucial 2010 World Cup qualifier against Croatia with a 2-1 win at Wembley on Saturday.
However, Johnson has been largely blamed for Slovenia's late goal in the latter stages of the encounter, with many now calling for the former Portsmouth right-back to be dropped by Fabio Capello for Wednesday's qualifier.
While BBC pundit Mark Bright has even gone as far to state that Johnson could cost England the World Cup should the Italian continue to persist with the 25-year-old in his back-line.
However, Rush - who made more than 450 league appearances for the Reds, has come out fighting from Johnson's corner, saying the stopper did not get any support from right-sided duo Shaun Wright-Phillips or Aaron Lennon ahead of him.
“Glen came in for some unfair criticism after England's win over Slovenia at Wembley. It reminded me of the stick John Barnes used to get when he played for the national side,” he said in The Sun.
“In Barnes' case when he played for Liverpool he was allowed to do what he wanted but when he played for England it was a much more restricted role.
“Maybe it's a similar situation with Glen because he has looked great for Liverpool so far.
“If you want your full-backs to attack then there's going to be space left at the back.
“In that situation you need help from your team-mates, especially the player in front of you, and Johnson didn't get that on Saturday.”
NEWS: Mark Bright - Johnson could cost England the World Cup
