Arizona Cardinals quarterback Kevin Kolb will be sidelined indefinitely because of cartilage damage in his ribs and a joint sprain, the National Football League team said on Tuesday.
Kolb, who was hurt late in Sunday's 19-16 overtime loss to the Buffalo Bills, is expected to be ruled out for "an unspecified period of time", the Cardinals said in a statement.
CT and MRI scans revealed no fracture in Kolb's ribs or sternum but showed a sprain in his sternoclavicular joint, between the breastbone and collarbone.
The 28-year-old is likely to be replaced at quarterback by John Skelton, who claimed the starting role from Kolb in the preseason before being sidelined with an ankle injury.
Kolb, who was hampered by various injuries last year, has led the Cardinals to a 4-2 record this season after starting in five of the six games he has played.
Arizona's next game is against the Vikings in Minnesota on Sunday.
(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue)