Guardiola is pleased with the recent improvement in City's defence as they conceded just three goals in six games since their embarrassing loss at Leicester a month ago, but a new defender is still on his wanted list.
City's weaknesses at the back, which were ruthlessly exposed in their 4-2 loss at the King Power Stadium on December 10, have led to speculation linking the club with Badstuber.
This has not been dismissed by Guardiola, who has hinted that defensive reinforcements could be made in January.
If we need something, maybe it's at the back, central defenders or full-back," he said last week.
Bayern will be reluctant to cash in on the German international and much will depend on the kind of cash that City put on the table if they do make a bid.