He will pick a formation to suit the opposition and that includes 4-4-2.
Plenty of options.
Nothing wrong with Lee Peltier, perhaps old fashioned right back that likes to tackle and distribute rather than go hung ho chasing over the halfway line.
With attacking midfielders you don't always need both full backs to push forward every time.
Lee Peltier was brought in for his experience, so was Sean Morrison both played together many times.They know each others game.
The club knew what they were getting when they signed them.