Shrewsbury have been forced to call off Saturday's home game with League One leaders Lincoln City following two more positive Covid tests within the club.
Steve Cotterill's relegation battlers have not played now since 29 December.
Lincoln boss Michael Appleton has himself been isolating after testing positive over Christmas.
Shrewsbury said in a statement: "We are reluctantly unable to fulfil our League One fixture with Lincoln City this Saturday following medical advice given to the club.
"Following further rounds of testing for all staff and players who returned a negative test previously, the club has been notified of two further positive test results.
"The club has informed Shropshire Public Health and the EFL of the current situation."
"We would like to place on record our thanks to our medical advisors, Lincoln City for their understanding, and Public Health Shropshire for their support and guidance."
Lincoln, who went four points clear at the top with Saturday's 1-1 home draw with Peterborough United, also suffered a Covid-related postponement at Hull on 29 December.
This is Shrewsbury's third home postponement in four weeks after Sunderland called off their pre-Christmas visit because of a Covid outbreak, although they did squeeze in the visit of Blackpool to Shropshire on 29 December.
Meanwhile, teenage Czech midfielder Jan Zamburek has returned to Championship side Brentford following the end of his three-month loan at Oteley Road.