Connolly has been given permission to rejoin the squad by the HSE and travelled back to Dublin this morning.
The Brighton & Hove Albion forward joins the five players who linked up with the squad last night; Dara O'Shea, Jason Knight, Ryan Manning, Ronan Curtis and Adam Idah.
: Darren Randolph (West Ham United), Caoimhin Kelleher (Liverpool), Mark Travers (Bournemouth).
: Matt Doherty (Tottenham Hotspur), Enda Stevens (Sheffield United), Shane Duffy (Celtic, on loan from Brighton & Hove Albion), Kevin Long (Burnley), Cyrus Christie (Nottingham Forest, on loan from Fulham), Dara O'Shea (West Bromwich Albion).
: Conor Hourihane (Aston Villa), James McCarthy (Crystal Palace), Jeff Hendrick (Newcastle United), Jayson Molumby (Brighton & Hove Albion), Jack Byrne (Shamrock Rovers), Robbie Brady (Burnley), Josh Cullen (Anderlecht), Jason Knight (Derby County), Ryan Manning (Queens Park Rangers).
: Aaron Connolly (Brighton and Hove Albion), Daryl Horgan (Wycombe Wanderers), Sean Maguire (Preston North End), Shane Long (Southampton), Adam Idah (Norwich City), Ronan Curtis (Portsmouth).
Connolly and Idah were ruled out of Ireland's Euro 2020 play-off semi-final clash against Slovakia in Bratislava due to close contact with an FAI staff member.
Following Ireland's penalty shootout defeat, it was discovered that the staff member's test was a false positive.
After missing the Slovakia and Wales games, Idah was one of the five recalled to the squad last night.
Connolly's name remained absent and he responded with a now-deleted tweet featuring a person sticking their hand up in the air.
However, the talented young forward has now been recalled to the squad and he flew back to Dublin from Brighton this morning.
Stephen Kenny's squad is due to fly out to Helsinki tomorrow.