Marcelo Bielsa has given an injury update on his skipper Liam Cooper and fellow centre-back Diego Llorente ahead of Sunday's Elland Road clash against Burnely.
Leeds United will be looking to bounce back from Sunday's 6-2 defeat at Manchester United when they host Sean Dyche's side this weekend but will again be short of numbers at the back after Cooper was ruled out of the clash.
"Cooper has a strain in his abdominals," Bielsa told the media in his pre-match press conference on Christmas Eve, but was unable to offer a return date.
"[That is] subject to his evolution," Bielsa added.
There was better news regarding Spain international Llorente, who returned to training earlier this week after missing the last three matches.
"Llorente is in conditions to play again," Bielsa said, putting Llorente in contention for his first Leeds United start after a groin problem sidelined him shortly after he completed his summer move.
Cooper limped off 72 minutes into Sunday's defeat at Old Trafford after having scored his first goal of the season shortly before half-time.
Llorente made his Leeds debut when he came on for Robin Koch in the early stages of the 3-1 defeat at Chelsea earlier this month.
Leeds will therefore have to play yet another defensive combination at the back, with Ayling likely to parter Llorente in the middle. Should Burnely utilise three strikers it would mean Leeds use three at the back, opening the door for Pascal Struijk to feature. Kalvin Phillips is another option here.
Koch underwent surgery on a knee problem that he had been carrying since the start of the season after the Chelsea loss and is expected to miss around three months, which would see him ruled out until early March.
He joins long-term injury victims Adam Forshaw and Gaetano Berardi on the sidelines.
Leeds currently sit 14th in the Premier League table, four points and two places ahead of the Clarets, who visit Elland Road on the back of 2-1 win at home to Wolves last week.
