The German champions, hunting a record-extending 11th straight league crown, are preparing for the January 20 Bundesliga restart at RB Leipzig with a training camp in Doha, Qatar.
"The preparation for the season restart is in full swing," Kahn wrote on Twitter on Monday. "The boys are highly motivated and I have full confidence that even without those long-term injury absences, we can still achieve our high goals."
Bayern are already without Neuer after the Germany keeper broke his leg during a skiing holiday last month following the World Cup and has been ruled out for the rest of the season.
Coach Julian Nagelsmann said his absence was a big blow as the club went in search of goalkeeping options in the transfer market.
"It is a very challenging situation for us," Nagelsmann said on Sunday. "It is not easy to decide what to do. We will see what is possible but at the moment there is nothing new to report."
France defender Lucas Hernandez will also be out for months after tearing ligaments during a World Cup group stage match in November.
Fullback Noussair Mazraoui is the latest casualty after suffering from heart complications due to COVID-19 during his post-World Cup vacation. He will be out for an indefinite period of time.
He had tested positive during the World Cup in Qatar, which forced him to miss Morocco's 1-0 quarter-final victory over Portugal.
Senegal international Sadio Mane did not make the trip to Doha as he is working on his own comeback from injury that had forced him to miss the World Cup.
The Bavarians also brought in Dutch defender Daley Blind on a free transfer and a six-month contract last week to fill some of the gaps.
