Minnesota Vikings wide receiver Jerome Simpson underwent an MRI on Monday that revealed it's an issue with his back that is causing weakness and numbness in his lower leg, according to an NFL source.
However, it remains unclear exactly what the problem is with Simpson's back and the veteran will undergo more tests.
Simpson was limited in Sunday's game against Tennessee after waking up with weakness and numbness in one of his legs.
Frazier said Monday that everything he has been told suggests Simpson won't be lost for a significant amount of time. But that could be different now that more testing will be required.