The Reds have endured a disastrous title defence this time around, sitting 12 points off top spot and in a scrap to even qualify for the Champions League.
While Souness acknowledged the importance of getting those players back to full fitness, the Scotsman also warned that his former side must spend this summer if they are to get back on track under Klopp.
"If Jurgen Klopp continues to play this way, which he will, Liverpool need to sign a couple of high-intensity, athletic midfielders," he told The Times.
"They also need their central defensive partnership of Virgil van Dijk and Joe Gomez back fit and settled, Alisson [Becker] back to the form he's shown before this season and Sadio Mane to start scoring again.
"Also, Diogo Jota, who has proved a good signing, needs to keep putting the front three under pressure for their places, if they want to get back to challenging Man City again."
Liverpool are back in Premier League action on Monday evening with a trip to Leeds United. body check tags ::