St Mirren have recorded no positive coronavirus tests prior to Wednesday’s Scottish Premiership game with Celtic.
The Paisley side were unable to name three goalkeepers for Saturday’s defeat by Hibs due to a Covid-19 outbreak.
Jak Alnwick, Dean Lyness and Peter Urminsky were ruled out, with Hearts’ Zdenek Zlamal drafted in on loan.
But following Sunday’s round of clear tests, Urminsky will be available for the visit of Celtic after being left out at the weekend as a precaution.
St Mirren said on Thursday that Alnwick was self-isolating after testing positive, then revealed a second goalkeeper – now confirmed as Lyness – had been found to have the illness.
Manager Jim Goodwin said he was “really disappointed” in the SPFL after claiming St Mirren were told they would have to use an outfield player in goal against Hibernian if they failed to register a new goalkeeper.
As well as bringing in Zlamal on an emergency loan three hours before kick-off on Saturday, the club had to register goalkeeper coach Jamie Langfield, 40, who was on the bench.
“It would have made an absolute mockery of the league,” said Goodwin on Saturday.
“If it had been three outfield players, we would have accepted it. I’m flabbergasted at what went on.”