Bayern concerns grow as Karl experiences back pain in rehabDuring today's rehab session, TZ Mnchen reporter Manuel Bonke captured Lennart Karl encountering difficulties at Sbener Strae.The Bayern Munich prodigy frequently grabbed his back while jogging around the pitch, often whilst grimacing in pain.Karl and teammate Serge Gnabry.are still under controlled workload and are behind Musiala, Davies and Saibari in their rehab.As previously reported, Bayern and player don't want to take any unnecessary risks with Karl to avoid aggravating his injury.This could happen if they put him under too much strain too soon. He's not expected to be available for the Super Cup against Dortmund.