Ribery has been out of action since suffering an ankle injury in the 7-0 drubbing of FC Shakhtar Donetsk on 11 March, while Schweinsteiger, who was absent for the last two games with an ankle problem of his own, has a virus.
Extensive injury list
"It's a shame Franck and Bastian can't make the trip," Sammer told the assembled press at Bayern's Säbener Straße training base on Monday. "Pep [Guardiola] will decide whether any of the younger players will make the trip."
The Bavarians were down to the bare bones for Saturday's 3-0 home win over Eintracht Frankfurt, with just 15 players named in the Matchday squad. Arjen Robben, David Alaba, Medhi Benatia and Javi Martinez remain sidelined, but Jerome Boateng and Claudio Pizarro are available again after shaking off minor knocks.