Karl, who has impressed with his composure and flair in limited Bundesliga appearances this season, including his first league goal against Borussia Monchengladbach in October, has been tipped as one of Germany's brightest prospects.
However, Nagelsmann has made it clear that the winger's international rise should be gradual.
"I've always said that I'm not a fan of hyping young players too much, too early," Nagelsmann said at a press conference on Monday. "Lennart is doing well at Bayern when he gets playing time, but first he has to go through the under-21s and prove himself there. He can play an important role at that level, which is the goal for every young Bayern player.
"At the moment, he still needs more Bundesliga minutes. It's too early for the senior team."
Karl has featured several times for Bayern this season under Vincent Kompany, earning praise for his direct style and attacking confidence. His performances have sparked comparisons with other rising German stars, including Koln's 19-year-old forward Said El Mala, who has just earned his first senior call-up for the upcoming World Cup qualifiers against Luxembourg and Slovakia.
Nagelsmann highlighted that both players bring attributes currently rare in German football. "They have different profiles," he explained. "We don't have many classic wingers who are strong on the ball and can cut inside effectively."
While a senior debut may have to wait, Karl's progression is being closely monitored by the national setup, recently earning a U21 call-up after his Champions League goal. With Bayern continuing to give him opportunities, and Germany's under-21s offering a vital stepping stone, his path towards a future international breakthrough looks well mapped out.
Bayern Munich, Borussia Dortmund and VfB Stuttgart were all in action in a dramatic Bundesliga Sunday that delivered dropped points at the top, a late rescue act in the Black Forest and a ruthless display in Bremen.
Saturday's Bundesliga action proved to be another goal-fest, with none of the fixtures ending in a draw and only two of the ten team's teams failing to score.
Ole Werner said experience made the difference after RB Leipzig were beaten 3-1 by Union Berlin in Friday's Bundesliga clash at the Stadion An der Alten Forsterei, with all four goals coming in a dramatic second half.
Bayern Munich have stepped up efforts to secure Serge Gnabry's future, with fresh negotiations pointing towards a two-year contract extension that would keep the winger at the Allianz Arena until 2028.
