Found this on a Vikings board about Richardson:
Tennessee Vol fan here. Word out of Knoxville is Tiny Richarson
Was supposed to be late 1st rounder. Until he got to the combine.
Doctors found out his knees are giving out. Both if them.
Might get 4 good years out of him. So his knees are what
Made him fall to being in drafted.
He stated he played on bum knees all last season. Looks
Like him coming out early and not getting treatment on his
Knees costed him.