The 21-year-old has caught the eye in Spain this season and his form has not gone unnoticed.
Indeed, according to Diario de Sevilla, Stoke have been scouting the midfielder and could move for him in January.
The Potters are said to have been watching Ruiz since August and scouts have returned with glowing reports.
Betis want to keep hold of the Spain under-21 international for as long as they can.
However, they could be forced into selling as he reportedly has a release clause of around £14m in his current contract.