It's only guaranteed if he is on the roster.

Roster bonus works like this: If you are on the roster when the bonus comes due, you get it. Typically these are broken down by game though. For instance you might get a 10 million roster bonus, divided by 16 (because there are 16 games). If a player only plays 8 games then, he would only receive half that roster bonus.

Galette's roster bonus was fully guaranteed, meaning that even if he missed half the games he would still get the whole thing. But even then, he doesn't get any of it if he is not on the roster come March 12.

Hope this helps.