Should you trust Chris Johnson this year?

I have received many questions about whether it would be smart to draft this player or that player and the majority of them have been about Chris Johnson. The last two years have been pretty sour for the former CJ2K and personally it would be hard for me to use either one of my first two picks (12/13) on him this year. Last year he started of the season frustrating Fantasy owners with a horrible per carry average and several pocket passers had more rushing yards than him after three weeks. Weeks 6-10 showcased what we fantasy nuts admire in Johnson. He had over 10 points each week including a 31 point performance in week 7 against the Buffalo Bills (ESPN.com Standard Scoring). Johnson finished off the season on an inconsistent note scoring less than 6 points three out of 7 weeks. Now as disappointing as last year was for the Titan RB it's a new season which means a new supporting cast. The Titans used their first round pick on my favorite player in the draft Chance Warmack and signed former Buffalo Bills guard Andy Levitre. Levitre was one of the best guards in the NFL last year while Warmack dominated SEC competition as well as Manti Te'o in the National Championship. The two guards in addition to bookend tackles David Stewart and  Micheal Roos (EWU's finest) seems like one of the best offensive lines in the country, pair that with the dismissal of offensive coordinator Chris Palmer and it looks like a good fantasy situation for Johnson right? Wrong, the Titans brought in Shonn Greene this off-season who's only good quality is his effectiveness on the goalline. That only takes TDs away from Johnson. Andy Levitre is also dealing with a nagging knee injury that keeps bothering him. I'm just so mixed on Johnson and I would only take him at the bottom of the second round in a 12 team league or top of the 3rd, and that's only if you snatched up a #1 RB in round 1.