Robertson, who has been one of Liverpool’s best players this season, picked up a late yellow card in the last-16 tie against Bayern Munich.
That was his third yellow of this season’s Champions League and rules him out of the first leg with Porto, with manager Klopp likely to pick James Milner to fill the Scot’s role.
That’s despite Alberto Moreno being available and in the squad to face Porto, with the Spaniard having not featured since early January.
Adam Lallana is likely to miss out tomorrow night with the midfielder having a slight muscle injury.
And Klopp is unlikely to risk Joe Gomez, despite the defender having travelled to Southampton on Friday as he looks to recover from a fractured leg.
Klopp said: “We wanted to have Joe around, not because he is now 100 per cent ready but it was just nice to have him.
“He could be maybe [available] but for him it’s better to have more sessions. Joe needs that, he is not long enough in training.
“If we don’t struggle players-wise, that we don’t have enough, then we should not think about Joe for the next one or two weeks because now he needs really proper training. He was around, that was good.
“Adam was only a little thing, we don’t have to talk about that. It kept him out for the weekend and maybe for tomorrow.”
“All the rest should be OK.
“We had little problems after the game [vs Southampton], back problems here, Gini Wijnaldum a little back problem, Joel [Matip], I think even Virg [van Dijk] from a fall on the ground.
“But they all should be OK, hopefully.”
Liverpool take on Porto having knocked the Portuguese side out of the competition last season.
The Reds won 5-0 in the first leg, in Portugal, in the last-16 before a goalless draw at Anfield.
Provisional Liverpool squad: Alisson, Alexander-Arnold, Matip, Van Dijk, Milner, Fabinho, Henderson, Wijnaldum, Salah, Firmino, Mane, Mignolet, Lovren, Moreno, Keita, Shaqiri, Origi, Sturridge