We are most fortunate to live in a country where the religious rights of workers are protected. Despite the hardships it may cause employers, workers can not be let go for observing religious rituals, including taking off for the various Yamim Tovim . In fact, Canadian law may go even further than Jewish law in this area. The Halacha has always maintained that religious practices not be allowed to interfere with a worker's obligations to his employer. One dare not be religious on somebody else's account. To do so distorts the true definition of piety as service of G-d is only meaningful if it causes heightened sensitivity to our fellow human being.
An employee is to devote their full energies to their employment tasks, including limits on activities outside of the workplace. It is not only highly paid athletes who (usually contractually) must refrain from other high risk activities. Any and all activities that might cause even small amounts of financial harm to one's employer are prohibited. One may not stay up late, diet, or take a second job if this would result in lower productivity than the norm. One may even require the bosses' permission to watch the late playoff games (sorry Leaf fans).
While it is understood that the employment culture of today allows and even encourages outside interests one must be careful to ensure that the limits not be extended unduly. Failure to adhere to these restrictions is legitimate grounds for dismissal in the eyes of Jewish law. More significantly even religious observances must at times be curtailed if they interfere with worker productivity. This includes not only religious stringencies and customs such as fasting for a Yahrzeit , or davening at the crack of dawn but also basic religious requirements. Thus Jewish law ordered employees to shorten their davening and curtail birchat hamazon (grace after meals). While these specific laws were formulated at a time when workers were expected to work from dawn to dusk the principles are of course still relevant. So while we do expect that one should begin one's day with davening and Torah study and perhaps even a morning jog one must be careful to ensure that these mitzvoth not come at the expense of an even more fundamental religious obligation, that of putting in an honest days work.