Leeds pair Rodrigo and Ian Poveda are expected to be out of action for several weeks, manager Marcelo Bielsa has confirmed.
Spain forward Rodrigo sustained a muscle strain in last weekend's win at Leicester and Poveda injured his ankle while in action for the under-23s.
Both players missed Wednesday's home defeat to Everton and will not feature in Monday night's game against Crystal Palace at Elland Road, live on Sky Sports.
"It's not a question of days, more of weeks," Bielsa said. "Rodrigo fell and his legs separated and caused an elongation more than usual and this caused the injury.
"I saw a picture of the position both of his feet ended up in and the difference between them was different to what we would expect."
Bielsa had better news on long-term absentee Gaetano Berardi, who has yet to appear for Leeds in the Premier League after damaging knee ligaments towards the end of last season.
The Swiss defender tore an anterior cruciate ligament in the victory at Derby in July, which required surgery.
"He's going to be returning to training on Monday with the team, and as he gains fitness he will start being incorporated with the under-23s," Bielsa said.
Bielsa's defensive resources have been stretched for most of the season following promotion to the top flight, with summer signings Robin Koch and Diego Llorente both currently sidelined.
Germany centre-half Koch was ruled out for three months after successful knee surgery in December.
Spain defender Llorente has been dogged by successive muscle strains since arriving for a reported £18m from Real Sociedad in September and has made just two appearances.
Leeds were beaten 4-1 by Monday night's opponents at Selhurst Park in November when Bielsa was out-foxed by veteran Palace boss Roy Hodgson, for whom the Argentine expressed his admiration.
Hodgson became the Premier League's oldest-ever manager when eclipsing Sir Bobby Robson in February 2019 and is still going strong at the age of 73.
"The career of Roy Hodgson deserves only praise and recognition," Bielsa said.
"To have the desire to extend his career for so long is something to admire and not only to do it, but to do it well."
When asked if he envisaged still being a manager at that age, Bielsa, 65, added: "It's very difficult to predict or calculate what's going to happen in eight years' time."