The midfielder missed the workout at Melwood, but is expected to re-join his teammates for Tuesday’s session.
Jürgen Klopp told reporters at his pre-match press conference: “Naby was ill yesterday, unfortunately, but I’ve heard now, I got a message, that he is back for today. We have to see how he is.”
Elsewhere, Klopp confirmed Dejan Lovren is making good progress in his rehabilitation from a hamstring injury - but won’t be available for selection against the Hornets.
He said: “[Dejan is] getting closer; they are all getting closer, thank God - the injuries don’t get more serious in our rehab.
“But no, not for tomorrow - nobody else coming back.”