According to talkSPORT, scouts watched Raum in action at the weekend when Leipzig beat Borussia Mönchengladbach 1-0, with the 27-year-old named player of the match. Liverpool's primary reason for attending was to observe £87 million-rated winger Yan Diomande, but Raum's performance reinforced his standing as a target in his own right.
Robertson, 32, will leave Anfield when his contract expires on June 30 after nine years at the club. He is understood to have a verbal agreement in place to join Tottenham Hotspur on a free transfer, subject to Spurs avoiding relegation. He confirmed his departure last week.
"I think I feel better now that it's out in the open," Robertson said. "The hardest bit [in] the last certainly couple of weeks and months is some people that are close to me in the training ground don't know and more importantly, the [fans didn't know]."
Liverpool see Raum as a player who could compete with Milos Kerkez for the left-back role rather than simply serve as cover. His attacking output — 27 assists over the past three seasons at an average of one every 3.7 games — and his leadership as Leipzig captain align with what the club is looking for. With one year remaining on his deal, he could be available at a reduced fee.
Manchester United are also tracking the Germany international, who is set to be part of Julian Nagelsmann's World Cup squad this summer. United need left-back cover with Tyrell Malacia expected to leave and Luke Shaw's injury record a persistent concern.
Leipzig want to keep Raum beyond this season, which may complicate any summer deal. The Bundesliga club are also attempting to retain Diomande, though they have already agreed to allow centre-back Castello Lukeba to depart, which could reshape their summer finances.
Antonee Robinson of Fulham is also understood to be on Liverpool's radar but would represent a more expensive option.