While Robertson said the move hasn't yet been confirmed, the Scotsman acknowledged the 29-year-old was a 'world-class' player.
"I've watched him, he's a fantastic player - a player full of talent," Robertson told Sky Sports News.
"He would add to the quality of a squad in probably any team in the world, so if we get him, great, if we don't then it is what it is. We'll wait and see until it's definitely confirmed.
"[Bayern Munich's] quality is there to be seen; we watched their Champions League final when we were away at pre-season, and they've got world-class players in every position pretty much, and he's definitely one of them.
"Look, [they are] a team full of quality and he's played at the highest level so fair play if we are linked with him."