Shelvey was hurt after he stepped in during an altercation between skipper Jamaal Lascelles and Mohamed Diame when tempers flared during the international break.
However, he will be fit to play, if selected, and is expected to wear a special cast.
Manager Rafael Benitez otherwise has no fresh injuries, with only defender Paul Dummett and Massadio Haidara still missing with hamstring and knee injuries respectively.
It means Javi Manquillo is likely to continue at left-back as the Magpies aim for their first win at St Mary's since 2004.
Provisional squad: Elliot, Darlow, Woodman, Yedlin, Manquillo, Mbemba, Gamez, Lascelles, Clark, Lejeune, Hayden, Merino, Shelvey, Saivet, Ritchie, Atsu, Murphy, Aarons, Diame, Perez, Gayle, Joselu, Mitrovic.