Rangers manager Mark Warburton could turn to Philippe Senderos in his search for a fourth centre-back after Joleon Lescott's Ibrox move fell through.
Warburton had expressed optimism on Thursday over the chance of signing Lescott, and the Aston Villa defender subsequently visited Glasgow.
But the move collapsed on Friday morning, with Rangers citing family reasons as the reason Lescott will not be signing for the club.
Villa owner Tony Xia had confirmed his club would pay a portion of Lescott's wages on the final year of his contract, but Sunderland have also been linked with the 34-year-old.