McDermott has a history of playing "system" guys who understand his complex defense over "take some risks, make some big plays" guys.
Elam is the latter.
Unfortunately, top offenses shred the system (because they are good enough to see and exploit the holes), and then you don't have the type of guys who make game changing plays.
A perfect example was signing A.J. Klein last year instead of playing Dorian Williams. If Willams had played he might have gotten burned a few times, but he may have made some big plays or stops, which Klein could not do.