Could they trade him for a second if it s the best offer they get , cause it would come soon.
No, I don't think they would trade him for a second. Especially if they were offered a first next year.Before the draft started today, I thought the most likely time for a trade announcement would be during the third round. I still think that.

why is that?
Because it seems like they've got a 2008 first-rounder in the bag, and were still negotiating to try to get a 2007 third-rounder thrown in. If they are successful, the trade would have to be announced during the third.If the Chargers can't get anything else, a trade could be announced anytime in the next few weeks (probably before May mini-camps).It's also still possible that he won't be traded, although that goes against the reports that the Chargers were offered a first next year and are willing to take it. But if he is traded, it will probably be announced either during the third or fourth round this year, or sometime after the draft.