St Helens captain James Roby has been ruled out of this weekend’s game against Wakefield with a rib injury.
Roby, 32, has started every game for Saints this season as they sit top of the Super League table.
He is replaced in Justin Holbrook’s 19-man squad by young full-back or centre Matty Costello.
Costello, 20, is yet to make his first team debut for Saints and has been with the club since the age of 14.
St Helens 19-man squad: Lomax, Makinson, Morgan, Percival, Fages, Smith, Amor, Taia, Wilkin, McCarthy-Scarsbrook, Douglas, Knowles, Thompson, Peyroux, Richardson, Grace, Lees, Barba, Costello.
Wakefield 19-man squad: Grix, Johnstone, Tupou, Lyne, Jones-Bishop, Miller, Finn, Wood, England, Ashurst, Kirmond, Randell, Horo, Arona, Huby, Arundel, Hirst, Baldwinson, Annakin.