Fred didn’t “bounce around”, and he was 26 when he joined the Bills. Because he was D3 he had a longer road, but he was co-MVP in the UIF in 2005 and rushed for 1700+ yds and scored 53 TD’s in 18 games, which are still single season records apparently. He was the leading rusher for the Rhein Fire in his only season with them. Despite the high profile competition, he outlasted and outperformed both Marshawn Lynch and CJ Spiller. Like Kurt Warner, FJax was the exception.
Johnson has been IN THE NFL for 5 years. He’s carved out a niche. He’s a valuable player. However, when Cook was injured against the Jets last season the Bills featured Davis, not Johnson. Three NFL coaching staffs so far have come to the same conclusion… he’s not a feature back.