Yet another unique challenge for this bizarre year...
Since the Bundesliga finished earlier than other leagues, the teams in CL & EL competitions face a large break. The obvious solution is to schedule friendlies as tune-up games, but the not-so-obvious problem is that whoever they schedule has to meet the Bundesliga Covid rules. Most of the Bundesliga is not on the testing protocol anymore because they're on summer break and won't restart training until later in Aug, and obviously international clubs have their own rules that might not fit the Bundesliga rules.
The easy answer was going to be to sort it out amongst the German teams in CL/EL.
Leipzig and Wolfsburg agreed to play on July 30.
Bayern scheduled a July 31 match against Leverkusen, but then Leverkusen backed out... deciding that the injury risk wasn't worth it (their opponent, Rangers, haven't been playing games either since Scottish league never restarted, and Leverkusen are up 3-1 after 1st leg, so I'm inclined to think they're being wise by not playing).
Frankfurt would be another domestic option, but they aren't seeking a friendly either (their opponent's league also hasn't resumed).
Bayern are now scrambling to find something that works for a July 31 friendly date. Rumor has it that's now going to be Olympique Marseille - Even though they aren't in CL/EL, I suppose with Ligue 1 having a relatively normal Aug 22 start date for next season that OM will already be back in training and doing precautions? Or maybe Bayern is money-whipping them to start a little early?
If all else fails, Bayern will have to play their reserves and then rely on their large lead over Chelsea to let that match also be a tune-up game of sorts.