Leeds United's injuries are piling up in defence and Marcelo Bielsa may be forced to delve into the under-23s should any other issues amount - but which players could make the leap if required?
Injuries to Luke Ayling and Gaetano Berardi, which have ruled the duo out at the very least until New Year, have left Leeds with only two fully fit senior centre-backs.
Kalvin Phillips has slotted into a back three on occasion when Bielsa has opted for the 3-3-1-3 formation this season but should Pontus Jansson or captain Liam Cooper pick up a knock the Whites are thin on the ground at the heart of defence.
In the 4-1-4-1 formation two central defenders are required and Phillips could of course be called into defence if needed to partner one of the two but that would take him away from his usual quarterback role that has seen him earn plaudits from the United faithful under the Argentine.
So... who are the other defenders at Thorp Arch that may be able to step into the first team if required in an emergency? We take a look at those options in the development squad...
The 22-year-old is perhaps at the front of the queue having been selected by Bielsa for the League Cup home defeat to Preston North End in August. Shaughnessy made a promising start to life under Thomas Christiansen as he made eight appearances under the Dane at Elland Road last season, with several coming in midfield, before being handed a new four-year contract after his performances.
The Irishman though picked up an ankle injury in January which ruled him out for the remainder of the season and has found the senior squad hard to come by under the Argentine having to settle for under-23s minutes this season.
Shaughnessy skippered Carlos Corberan's side on Monday in the 3-1 defeat at Crewe Alexandra in the Professional Development League with Bielsa in attendance and is more than likely next in line should he be required after a glowing reference from El Loco earlier this year.
The Spaniard, who joined the club in 2017 from Deportivo La Coruna, linked up with the under-23s initially as he formed a strong partnership with Paudie O'Connor - who is out on loan at Blackpool - in the development team last season.
Diaz was included in several match day squads by former boss Paul Heckingbottom before being handed his debut amongst an injury crisis at Preston North End last season as he stepped off the bench in place of Pontus Jansson during the defeat at Deepdale.
The 21-year-old has made a number of appearances for Corberan's side this season but has found minutes hard to come by in recent weeks with Leif Davis moving across into the middle from left-back.
Leeds added the highly rated Finnish defender to their ranks in January from HJK Helsinki with the 6ft 4in centre-back signing a four-year contract in West Yorkshire.
Following an injury to his foot during a training session, which resulted in surgery, Halme was ruled out for the rest of the campaign and spent nearly nine months on the sidelines before making his debut for the club against QPR in the Professional Development League in late August.
Halme has put in a number of strong performances for the under-23s, particularly against Bolton Wanderers during their first defeat of the season in September, but picked up a knock two weeks ago against Notts County in Premier League Cup action.
The club are yet to give an update over the defender but he has failed to feature in the last two match day squads for Corberan - it seems his Leeds United career just can't get going despite his obvious talent.
Another defender who joined Leeds in January as the 18-year-old made the move from Ajax to Thorp Arch. The commanding centre-back looks beyond his years in stature and has turned out regularly for the under-23s side since his arrival last winter.
Struijk was named in the match day squad to face Aston Villa last season by former boss Paul Heckingbottom during the injury woes at Elland Road but is yet to make any appearances at first team level for the Whites after being brought it as a future prospect from Holland.
Honourable mention... Leif Davis
The 18-year-old full-back joined the Whites in July from Morecambe and after a string of appearances at left-back has recently also been deployed in the heart of defence by Corberan.
Davis' ball playing skills fit Bielsa's style of football but his place in the centre nullifies his pace on the flanks. United could, if required, call upon him for his services in the middle after proving himself more than adequate at centre-back but the youngster possesses more natural skills at wing-back.