Johnston, 49, says the goodwill of the Anfield fans is probably the only thing keeping the Spaniard from the chop.
"You see one win in nine games, six defeats in the space of eight games, you see a dejected look on players' faces. Has he lost the dressing room? Six defeats in eight games would say that he has," Johnston told the Daily Star Sunday.
"Has he lost a bit of the board's backing? Well you hear what Liverpool co- owner George Gillett's saying about him in the papers. He actually said that he's made bad signings, the team's not playing well and there's no youth coming through. And this is from your employer.
"I think people think Rafa is a genuine and sincere bloke and that goes a long way with Scousers - but there are things going against him now."