An investigation is to be launched after an unnamed Republic of Ireland player returned a negative coronavirus test just hours after testing positive.
Connolly, along with Adam Idah, was withdrawn from the squad ahead of Thursday night's Euro 2020 play-off semi-final in Slovakia following what proved to be a false positive result for a member of the non-football staff.
A Football Association of Ireland statement said: "The Football Association of Ireland can confirm that a member of Stephen Kenny's Ireland squad has returned a negative result from a second COVID-19 test today after first returning a positive result from a UEFA test undertaken on Sunday evening.
"The player – who cannot be named at this time – first received a positive result from the UEFA testers on Monday morning in the latest round of UEFA testing for COVID-19 ahead of the Nations League game against Finland in Helsinki on Wednesday.
"The FAI medical team then organised a second test for the player which returned a negative result this afternoon.
"The player will now be retested as soon as possible before the team's flight to Finland on Tuesday morning. The HSE and UEFA have been informed of this result."
Coronavirus protocols have severely disrupted manager Kenny's plans over the last week, with Connolly due to start in Bratislava where Ireland ultimately lost on penalties.
John Egan, Callum Robinson, Callum O'Dowda, Alan Browne and Derrick Williams all missed Sunday's 0-0 draw with Wales in Dublin after another unnamed player tested positive.
The fact that the 20-year-old Brighton striker and Norwich counterpart Idah could have played after all did little to ease the pain of defeat, and the latest negative test has served to further focus minds.
FAI interim chief executive Gary Owens said: "This negative result following a positive has been reported to UEFA and the HSE and we are in communication with both UEFA and the HSE regarding the player's availability for the Finland game."
Connolly's return to Dublin – he had initially been sent back to his club – at least helped to ease Kenny's selection headache.
An FAI statement on Monday morning said: "Republic of Ireland striker Aaron Connolly has rejoined the squad ahead of the UEFA Nations League match against Finland on Wednesday.
"Connolly has been given permission to rejoin the squad by the HSE (Health Service Executive) and travelled back to Dublin this morning."
He and Idah had to miss out in Slovakia because they had been sitting within two metres of the supposedly infected staff member on the flight over, with Connolly, it was later revealed, just 10 centimetres too close.
Nineteen-year-old frontman Idah had already been given the all-clear to meet up with the squad once again.
The Republic's ranks were further depleted when defender Kevin Long had to leave the field with a badly swollen eye after a clash with Wales striker Kieffer Moore, and midfielder James McClean was later sent off for a second bookable offence.
Kenny, who was already without the injured Seamus Coleman, James McCarthy, David McGoldrick, Harry Arter and Darragh Lenihan, has also called up West Brom defender Dara O'Shea and Derby's Jason Knight, who were on Under-21s duty in Pisa ahead of Thursday's European Championship qualifier against Italy, and QPR's Ryan Manning and Portsmouth's Ronan Curtis.
Ireland have taken just two of the first nine Nations League points on offer – they drew 1-1 in Bulgaria before the stalemate against Ryan Giggs' men either side of a 1-0 home defeat by Finland – and are yet to win in four attempts under their new manager.