It depends on the rest of your team and needs, but I don't think it's a bad time.
If you have RB depth, feel free to make a move for an upgrade elsewhere, but I think LT is going to have RB2 value for the rest of the year. If you need that RB, hold onto him.
I just traded him myself but he was my 4th or 5th RB and I needed a top WR. I got R. Moss for LT and Vick. Of course, I'm having my doubts after Moss' 0 tonight.