This is becoming close to being a full time business. In the old days, players would have offseason jobs to support their income and didn't have time to train year round. Nowadays, guys make millions a year. Even UDFA's make three times as much as I do. There is really no good reason to NOT work at football all year. The new CBA should specify that a team has the right to your services from March 31 (or perhaps earlier) until your team's season ends. That's still WAY more vacation than I get per year. Until that time, we're gonna have to put up with all this stuff about guys working out on their own and taking this "voluntary" thing literally.
Right now, I don't have a problem with Haynesworth working with his own trainer but you have to be an idiot to not show up at a minicamp, an extra one granted by the league for a new HC, where things like offensive and defensive strategies can be installed.