Actually, Matt Shelton was, running a 4.29.
ahh yes you're probably right my friend, my point was though that the fastest guy isn't always the best returner. Shelton was an awful returner as I'm sure we all remember, and he was the fastest player on the team last year.
Willingham probably figured what most fans think, stick the fastest guy back there,hence the reason he let Selton return kicks, which turned out to be an awful mistake as we saw how bad a returner Selton was Ty's last year.
Currently I'm fine with the Grimes,and West combo, Grimes is soilid, and I haven't seen enough of West yet to speculate. Weis saw something in TommyZ that the previous coaching staff, and most fans in general didn't see, that he is a helluva punt returner. Weis was smart enough to see the punt returner potential in Tommy Z(even though he is an unconventional returner), therefore I trust his judgement on the return game.