Karl suffered a serious muscle tear in his thigh shortly before the start of the World Cup, a blow that ruled him out of the tournament entirely. The winger began running training around ten days ago, but sharp changes of direction still appear to be too soon for the youngster, whose rehabilitation programme continues to be managed cautiously by the club's medical staff.
Bayern Munich have been in no rush to accelerate Karl's return given the significance of the injury and his importance to Vincent Kompany's long-term plans. The teenager broke through emphatically last season and is regarded as one of the club's brightest talents, making the prevention of any setback in his recovery a priority over a swift return to full training.
With pre-season already underway, Karl's continued absence means he is likely to miss the bulk of Bayern's preparations before the new campaign, though a gradual return to full training remains on track in the coming weeks.
The teenager's rise to prominence at Bayern came in the first half of last season, when he established himself as a regular contributor in Kompany's squad at just 17 years old.
His absence through injury coincided with growing competition in Bayern's attacking ranks, with the club having strengthened the position further over the summer, adding an extra layer of urgency to Karl's eventual return once he is fully fit.
For now, the focus remains squarely on ensuring the youngster returns to full training without risking a fresh setback, even if that means sacrificing valuable pre-season minutes ahead of the new Bundesliga season.
Missing the World Cup was a significant blow for Karl personally, given the timing of the injury just days before the tournament got underway, but Bayern's medical staff have been clear throughout that a phased, patient approach offers the best chance of a clean recovery without further complications down the line.