Rangers have made enquiries to Sunderland for duo Dan Neil and Romaine Mundle — and are also keeping tabs on Hibs striker Kieron Bowie.
It comes as the Ibrox club were also closing in last night on a double swoop for Sturm Graz midfielder Tochi Chukwuani and Westerlo left-back Tuur Rommens.
Chukwuani, a Danish Under-21 international, is expected to join for a fee of around £4million, whilst Rommens, who has also played for Belgium at Under-21 level, should join for around £3m.
Now firmly established as serious contenders in this season’s title race, Rangers are keen to back Danny Rohl as much as possible in the January window.