Xavi will have to continue to rotate, with two games every week until/unless getting knocked out of Copa and Europa League. Xavi has been doing a good job with squad management, I can even almost understand why he keeps giving Ferran chances.
The good omen is that all 5 midfielders are playing great. Of all the players in the rotation (so not Eric, not Bellerin), only Ferran has been looking bad. If the team can survive these two games without Lewa, I'm pretty optimistic about the rest of the season.