Huddersfield Giants’ contest against Wigan Warriors - also scheduled for Friday - was postponed yesterday due to seven positive tests in the Giants ranks.
And Leeds’ televised clash at Emerald Headingley has now also been called off after Rhinos reported two players had tested positive.
A joint RFL/Super League statement read: “Two of the Leeds senior squad have tested positive for Covid-19 in the last two days, requiring them to self-isolate for 10 days - and an additional seven players have been shown as close contacts of one or both of those players through Test and Trace.
“Under the RFL's Covid-19 protocols, a team can apply to postpone a match if seven or more senior players are unavailable as a result of Covid-19 - either through positive tests or as close contacts - and the RFL have therefore accepted Leeds' request to postpone Friday's fixture.
“As with the Huddersfield Giants versus Wigan Warriors fixture, which has also been postponed as a result of Covid-19, the clubs will liaise with the RFL on a possible date to rearrange the match later in the season – although the Betfred Super League table will again be determined by win points percentage to allow for the possibility of not all fixtures being fulfilled.”
Sky Sports had been due to show the Rhinos versus St Helens game but will now cover Hull KR against Salford Red Devils (kick-off 745pm).
Rhinos released the following statement: "The Rhinos currently have two players who have received a positive COVID-19 test whilst seven players are self-isolating following track and trace.
"Since last weekend, one player is self-isolating after being contacted by NHS test and trace having come into contact with a member of the public who had tested positive.
"On Monday, during the routine lateral flow testing at the club, a player tested positive which has been confirmed with a subsequent PCR test. That positive result meant two more players had to self-isolate.
"On Tuesday morning, another player returned a positive lateral flow test, which led to four players being ruled out through contact tracing from Monday’s training session.
"There were no additional positive COVID-19 tests in the previous round of Lateral Flow Tests on Monday and again on Wednesday morning for all players and staff. The remaining fit and available players will train as normal on Wednesday at the club’s training ground.
"The two players who tested positive are being monitored by the Leeds Rhinos medical staff, and in the interests of privacy, the club will not be disclosing their names."
The Huddersfield game was the first fixture this season postponed due to the pandemic.