Goalkeeper/defence
Since the beginning of his interim reign, John O’Shea has consistently picked strong starting XIs and avoided going down the experimental route, so expect Caoimhin Kelleher to feature again in the Portugal match.
Against Hungary, Ireland looked a bit more solid in the second half when Liam Scales and Jake O’Brien were introduced, so it would be no surprise to see the latter handed a full debut. Dara O’Shea completed 90 minutes in last Tuesday’s game and will probably keep his place in the team.
After looking a little sluggish in the first half against Hungary, Shane Duffy might have to settle for a place on the bench.
Wing-backs
Matt Doherty and Robbie Brady started in these positions last Tuesday, but neither were particularly impressive and both players had been withdrawn by the 62nd minute.
So it is an area where O’Shea might opt to freshen things up. Callum O’Dowda looked lively when he was introduced in the second half of the Hungary game. Seamus Coleman also looked more solid than Doherty after moving from centre-back to right wing-back, so Ireland could conceivably start the way they finished last time.
Enda Stevens will hope to feature at some point too after being held in reserve last Tuesday.
Midfield
It would be harsh to drop Will Smallbone after his man-of-the-match display against Hungary and Josh Cullen almost always starts, so this is an area where changes seem most unlikely.
Jamie McGrath and Mark Sykes will aim to get some minutes, most likely from the substitutes’ bench.
Attack
Adam Idah took his goal well on Tuesday, and with John O’Shea ostensibly trying his utmost to land the permanent manager’s job, he will probably go again with the in-form striker who also recently notched the winner for Celtic in the Scottish Cup final and managed nine goals from 19 appearances since moving to Glasgow.
Troy Parrott may be rewarded too for his winner against the Hungarians, even if he is perhaps a somewhat awkward fit into a three-man attack.
Ireland are playing the team ranked sixth in the world, so it’s also possible O’Shea will go for a more defensive option like Jason Knight in the wide position.
Finn Azaz struggled to make an impact last Tuesday and so may have to settle for a place on the bench, though as one of Ireland’s biggest goal threats, Sammie Szmodics should keep his place.
Other attacking options include potential debutant Tom Cannon, Mikey Johnston and Michael Obafemi, with the latter getting 20 minutes to impress against Hungary.
Ireland (3-4-3): Kelleher; Scales, O’Brien, O’Shea; Coleman, O’Dowda; Cullen, Smallbone; Parrott, Szmodics; Idah.
Republic of Ireland Squad – Portugal
Goalkeepers: Caoimhin Kelleher (Liverpool), Mark Travers (AFC Bournemouth), Max O’Leary (Bristol City), David Harrington (Fleetwood Town)
Defenders: Seamus Coleman (Everton), Matt Doherty (Wolves), Shane Duffy (Norwich City), Dara O’Shea (Burnley), Jake O’Brien (Lyon), Liam Scales (Celtic), Robbie Brady (Preston North End), Enda Stevens (Stoke City).
Midfielders: Josh Cullen (Burnley), Finn Azaz (Middlesbrough), Jason Knight (Bristol City), Jamie McGrath (Aberdeen), Callum O’Dowda (Cardiff City), Will Smallbone (Southampton), Mark Sykes (Bristol City), Mikey Johnston (West Bromwich Albion, on loan from Celtic).
Forwards: Sammie Szmodics (Blackburn Rovers), Adam Idah (Celtic, on loan from Norwich City), Troy Parrott (Excelsior, on loan from Tottenham Hotspur), Michael Obafemi (Millwall, on loan from Burnley), Tom Cannon (Leicester City).