No, he plays far faster than his timed speed. He said in his interview he lost some weight and plays at about 205lbs and said he feels so much faster. I'm I remember correctly he was hobbling when he ran that bad 40 time. He is very fluid, has instincts and can find the football while making very athletic adjustments. He should challenge the top free safety's in the league.
I like Arizona's coach. However I don't think he realized everything Jefferson could do. When a player is undrafted he really has to prove himself every step along. He was already fast enough but if he did get faster he may be a better free safety. He can do it all!! Cover tackle, top shelf instincts, play shallow and long when he has the opportunity. His best play is yet to come. He was thought of as a round1 player until combine.