There are a lot of complexities here. I'll explain the situation as simply as I can, but it's still complex.
Here are the facts.
1. The last date for any player to sign is the Tuesday following the tenth week (not the tenth game) of the season — in this case, November 16. If VJ does not sign by November 16, he cannot play this year. (That is just after the Chargers' bye week, so if VJ ends up signing with the Chargers for some reason, he would very likely sign at least a week early: no later than November 9. That's because players are paid during their bye week. Whether he reports Nov 9 or Nov 16, he'd play the same number of games, so there's no reason for him not to collect an extra paycheck.)
2. The current CBA (which will terminate after this season) allows players to become unrestricted free agents after they have accrued four seasons — except in uncapped years, when the requirement goes from four seasons up to six seasons. This is an uncapped year.
3. In order to earn an accrued season, a player must be eligible for six games. (More specifically, a player has to be on "full pay status" for six games. To be on full pay status in a given week, a player has to report in time to practice during the week of that game — he can't simply report five minutes before kickoff.)
4. VJ already has five accrued seasons.
5. Also, there is a provision in the current CBA which says that a player cannot go from restricted free agency to unrestricted free agency by sitting out the whole year — regardless of the number of accrued seasons he has.
6. VJ will be suspended from weeks 1–3 this season.
7. A player cannot report to his team during his suspension.
8. VJ has been placed on the roster-exempt list, which makes him ineligible to play in the three games following his report date. (The roster-exemption will apply whether or not he is traded.)
9. The Chargers' first game is September 13. The week of practice preceding that game starts September 4. (Two days after the final preseason game.)
10. The Chargers have a bye in week 10.
11. The trade deadline this year is October 19, after the week 6 games.
And here is what it all means for VJ.
1. VJ will not play weeks 1–3.
2. To be eligible to play in week 4, VJ would have to report by September 4. That way, the roster-exemption will make him ineligible during weeks 1-3, the same weeks as his suspension.
3. If he doesn't report by September 4, he won't be able to report until after the week 3 game of September 26. Whenever he does report, he'll be ineligible for the following three games.
4. To get an accrued season, VJ would have to report to the Chargers by October 26, so that he'd be on full pay status for the Halloween game in week eight. (If he is traded to a team that has its bye before week 9, he wouldn't have to report until November 2.)
5. VJ almost certainly does not need an accrued season, however. He already has five, and there's almost no chance that a new CBA would require six accrued seasons for unrestricted free agency.
6. To avoid sitting out the year, VJ would have to report by November 16, the NFL signing deadline. If he does report November 16 (or November 9 for the Chargers' bye week), he would be eligible to play the final four games of the season in weeks 14-17.
7. For purposes of becoming an unrestricted free agent, however, it probably doesn't matter whether he sits out the whole year. The current CBA says that a player can't go from restricted status to unrestricted status by sitting out a year, but any new CBA would very likely make VJ (and players like him, who already have at least four accrued seasons) unrestricted free agents. The players' union would want VJ, McNeill, and Mankins to be unrestricted free agents, and 30 of the 32 NFL owners probably would as well. (It's not a sure thing, though, and if I were VJ's agent, I'd have him report by Nov 16 to erase any doubt. I'm not VJ's agent, however.)
8. If VJ does become an unrestricted free agent in 2011 (or whenever the next season is), the Chargers would very likely (but not certainly) be able to slap the franchise tag on him if they wish.
9. So the important deadlines for VJ to sign are: September 4 (to allow him to play 13 games), October 26 (to allow him to play 6 games and get an accrued season), and November 16 (to allow him to play 4 games and avoid sitting out the season).
My guess.
I think the two most likely scenarios are: (a) VJ is traded and signs before September 4 [technically, he'd have to sign before he is traded]; or (b) VJ is not traded and sits out the whole year, likely (but not certainly) becoming an unrestricted free agent the following season (whether that's in 2011 or a later year). The latter possibility is looking fairly likely if VJ doesn't drastically reduce his salary demands pretty soon.