Kilmarnock midfielder Rabiu Ibrahim has spent a second night in hospital after collapsing on the pitch during Saturday's 2-0 win over Ross County.
The 22-year-old, who was signed from Celtic in the January transfer window, lay on the pitch for several minutes before he was stretchered off and taken to hospital.
Killie manager Allan Johnston visited the player at University Hospital Crosshouse on Sunday night.
"They are keeping Rabiu in to do further tests," said Johnston.
"He is feeling fine so hopefully that is a good sign. I watched the DVD of the game again - he just sits down in the middle of the park and then lies down. But nobody touched him."