Salah scored twice to reach a half-century of Liverpool goals in midweek in a comfortable victory over Red Star Belgrade.
But he looked miserable afterwards – barely celebrating his strikes – and Merson thinks that is a clue to how he is feeling at Anfield.
And, with Real Madrid struggling and in desperate need of turning round their season, Merson thinks the move is on the cards.
“Mo Salah’s goals record for Liverpool is phenomenal but it’s only a matter of time until Real Madrid come calling,” Merson told the Daily Star.
“That’s some record, to be the fastest man to score 50 for Liverpool, especially when people are saying you are having a bad season!
“But if he keeps on scoring Madrid will come calling.
“How can they not? They need to do something big and they will want him in January. They are struggling like mad.
“If Salah wanted to go, Liverpool would be powerless to stop him.