I dont think you can start Jones in base packages yet...
Getting him 1 on 1 vs any wideout with some burners will put us in trouble everytime in the beggining..
http://www.nfl.com/videos/nfl-combine/09000d5d816dce91/2010-Combine-workout-Reshad-Jones
Go to :7 seconds in. Watch his combine workout, his swiveling of hips is below average and takes him time to transition. In the bears game his angles got eaten up a bunch of times when trying to attack the ballcarrier.
I love him in Nickel and Dime packages where he can just roam and use his ballhawking ability. But until he learns how to use angles right and understands his cushion I dont think you can start him fulltime.
The dilemma is that with Clemons in, we have a sure-fire safe FS who will make very little mistakes but won't cause that many turnovers.
Then you have Jones who is a loose cannon per se. He can cause havoc back there, but he can also suffer several mental lapses and give up big plays.
With Clemons your looking at a #5-8 defense consistently, maybe peaking at #3,4. With Jones your looking at either a #1-3 defense or #8-11 ranked defense.