Cape Town - Lions captain Warren Whiteley is a fitness concern with a pectoral injury following Saturday's loss to the Stormers in Cape Town.
The 31-year-old left the field shortly before half-time on Saturday and did not return as the Stormers secured a last-gasp 19-17 win over their visitors.
"It doesn't look too positive," Lions coach Swys de Bruin said of his leader in his press conference.
"I saw his reaction in the dressing room, but we will have to wait and see."
Whiteley was set to go for scans and tests on Monday and a further update is only expected on Monday afternoon at the earliest.
The Lions are next in action when they host the Bulls at Loftus on Saturday.