Manager Brian Kerr has one enforced change due to Jim Goodwin, sent-off in Thursday's opening game, receiving a two-match suspension. He may also opt for a second.
"In tournaments like these it's always good to try to freshen up the team," said Kerr. "The same legs can't do it for you in every match."
Goodwin's dismissal against South Africa was the third in the last four games for this side, but Kerr was quick to refute any suggestion of a disciplinary problem within the squad.
"It's annoying, but not something that causes me great grief as they weren't nasty incidents. These are young players who sometimes do rash things. They have to learn."
With the South Africans scarcely having troubled his side, Kerr knows Spain represent a different proposition.
"It will be a much tougher game, both physically and technically," said Kerr. "They weren't brilliant in drawing 0-0 with Egypt, but they are a good side.
"We know that if we win today we're through to the semi-finals with a game to spare, whereas if we lose it's down to a right scrap with Egypt on Monday."
Leeds United's Dundalk-born Bryan McCrystal is the obvious choice to come in to partner John O'Shea in central defence. The other possible change could see Thomas Butler in for Brendan McGill, who had a quiet first game.
Probable Team (4-3-3): Murphy (Tranmere Rovers); D Byrne (Stockport County), O'Shea (Manchester United), McCrystal (Leeds United), Foy (Nottingham Forest); Dempsey (Everton), Miller (Celtic), S Byrne (West Ham); McGill (Sunderland), McMahon (Newcastle), Reid (Nottm Forest).
Referee: Sergey Shmolik (Belarus).