Gámez – likely to start at right-back, with Javier Manquillo on the opposite flank – has yet to appear for United in the top flight this term, while Murphy has been restricted to two substitute appearances.
The latter comes in for Christian Atsu, who appeared twice for his native Ghana during the international break.
Joining Atsu on the bench is Jonjo Shelvey, who will hope to play a part against his former club after completing his three-match suspension.
With Shelvey a substitute, Mikel Merino – who impressed in last month’s 3-0 win over West Ham United at St. James’ Park – keeps his place in the side.
Merino’s fellow Spaniard, Joselu, starts up front, while Dwight Gayle – still searching for his first goal since the Magpies’ return to the Premier League – is back in the squad.
After returning to full training last week, DeAndre Yedlin and Florian Lejeune both make the bench, too.
Newcastle United: Rob Elliot, Jesús Gámez, Jamaal Lascelles, Ciaran Clark, Javier Manquillo, Isaac Hayden, Mikel Merino, Matt Ritchie, Jacob Murphy, Ayoze Pérez, Joselu.
Substitutes: Freddie Woodman, DeAndre Yedlin, Florian Lejeune, Jonjo Shelvey, Mohamed Diamé, Christian Atsu, Dwight Gayle.