nah, a team sport means that you play as a team and train as a team but it doesn't mean you forfeit your right to individualism. While he is contracted he has to accept his lot as a winger but he doesn't have to do that indefinitely. his contract doesn't end until the end of 2015 and all he has done is said he isn't going to commit beyond that. he is absolutely free to look elsewhere if he wants to after that. it is no different to a team deciding to not re-sign a player because there is a better option on the market.
as for the employment thing, you're talking about a separate issue. People get fired for not working as a team but that isn't what is happening here with Hoffman (or at least what the article is about). If Hoffman skips training or complains non-stop then there is a problem but there isn't an issue with looking elsewhere for a job when your contract is coming up for renewal. As an employer, if you fired an employee for considering other jobs or putting negotiations on hold when their contract was ending, you'd actually be in some serious legal trouble for wrongful dismissal.
The problem here is people are merging the idea of putting negotiations on hold with actually being a fuckwit during training and games. The second one is a huge issue, the first one is a non-issue in my opinion. Personally I think it would be better for his career and for Brisbane if he stayed and played on the wing/centre but he is entitled to do what he likes after 2015