Leeds' game with Aston Villa on Tuesday is the latest Premier League game to be postponed.
A combination of Covid-19 cases and injuries in the Leeds squad saw them request a postponement, which was granted by the Premier League.
Leeds' match against Liverpool on Boxing Day had already been postponed due to the virus.
The club said in a statement: "While there have been no new Covid cases in the playing squad, the majority of those who tested positive prior to the Liverpool game are not yet out of isolation.
"Therefore, we still do not have enough recognised first-team players to meet the Premier League requirements for the fixture."
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The Premier League said it accepted Leeds' request for a postponement as did it not have 13 outfield players and one goalkeeper available for the match.
A Premier League statement read: "Following a request from Leeds United, the Premier League board met today [Sunday] and regrettably agreed to postpone the club's home fixture against Aston Villa, due to be played at 5.30pm on Tuesday, December 28.
"The board was able to make its decision in advance of the match to give clarity to the affected clubs and their fans. We apologise for the inconvenience and disruption caused to supporters' festive plans."
Aston Villa have also been impacted by Covid-19. Manager Steven Gerrard will miss their Boxing Day match against Chelsea after testing positive while last weekend's game against Burnley was postponed two hours before kick-off.
What are the Premier League rules around postponements?
After the postponement of a number of games in the weeks leading up to Christmas, a new Premier League guide explaining match postponement protocols was published.
And there, these factors are considered when deciding whether to postpone a top-flight game:
- The impact of COVID-19 infections on a club's squad, as well as injuries, illness and those isolating, and the number of players available on the squad list and any Under-21 players with appropriate experience. Where a club cannot field 13 outfield players and a goalkeeper either from its squad list or its appropriately experienced Under-21 players, the match will be postponed.
- The status of any COVID-19 outbreak within a club, including the number of individuals affected, the sequence and source of infections and their proximity to the match in question.
- A club's ability to safely prepare its players in the lead-up to a match.
- Medical advice as to whether there is any unacceptable risk to the health and safety of players and staff by playing the match.
- Any advice from UK Health Security Agency and other public bodies.
- Any other exceptional circumstances.