But Diego Gomez is back in contention for Sunday’s Premier League clash after missing the draw with Everton.
Ayari left the Amex last Saturday with his arm in a sling.
He has been a key player in midfield for the Seagulls but his absence could open the possibility of Pascal Gross partnering Carlos Baleba in the engine room.
That looks a potentially exciting duo in midfield and fans had a glimpse of it in the final half-hour against Bournemouth recently.
Gomez will immediately become an option for a right-of-centre berth after the departure of Brajan Gruda on loan to Leipzig.
Georginio Rutter played on that side against Everton with Yankuba Minteh later going on as substitute.
Right-sided midfielder Harry Howell was an unused substitute for the Everton game and will again be part of the matchday squad.
Mats Wieffer remains absent but Fabian Hurzeler said he is getting closer to a return after a toe injury.