That's why Pep made some rotations especially for the young players when they played in smaller competitions like the EFL yesterday.
Rodri's position is now vital because after all, Rodri is one of the players who has always been an important part of the squad just like KDB considering these two players are the most central in midfield.

KDB is used as a more complex player for attack while Rodri is used as a defensive option and helps balance the midfield. Now the loss of Rodri could have an effect but there are several players who are likely to be projected to fill in. Kovavic could be an option but when they want younger Rico Lewis or O'reilly could be projected although Rico Lewis is a right-back by trade but he could also be used as a defensive midfielder when there are no other options for Pep.