For members of The Church of Jesus Christ of Latter-day Saints, the Ten Commandments are very much in effect today. The fourth commandment, to remember the Sabbath day and keep it holy, is heavily emphasized within church doctrine and culture (Exodus 20:8; Deuteronomy 5:12). This command to set apart the Sabbath is observed on Sundays for the LDS Church as well as the majority of the Christian world, rather than the traditional Saturday. Though the Ten Commandments collectively have both individual and societal implications, the spiritual outcome from following them is indeed an introspective pursuit. This thesis seeks to address how members of the Church seek to keep the Sabbath day holy in a profession that is heavily involved in Sunday work. With the universality of sports among Latter-day Saints, and large numbers of youth hoping to play sports professionally, this study is timely because it seeks to elucidate the effects that playing professional sports, particularly in the NFL, have on church activity. Chapter One details the history of the Sabbath from the Old Testament to the present day. It then discusses the doctrine of the Sabbath as taught by the LDS Church. It also discusses what the highest officers in the church, the First Presidency, Quorum of the Twelve Apostles, and other auxiliary leaders have said about sports and Sunday play. It finishes off with a description of the research methodology and the interview process for thirty Latter-day Saints who played in the NFL. Chapter Two introduces the data and some of the main findings regarding Sabbath day worship in the NFL; it highlights the sacrament, church attendance, and other personal religious habits for these athletes. Chapter Three continues the discussion of the data and more particularly addresses some of the challenges more pertinent to LDS NFL players. It was apparent after the interview process that these participants found it challenging to be in an atmosphere so incompatible to their personal beliefs, including religious criticism from teammates, harsh language, lewdness in and out of the locker room, and many other difficult circumstances. Marriage is addressed and how it was a major factor for these players. It also includes quantitative information about the athletes' backgrounds and faith experiences leading up to their careers in the NFL. Chapter Four summarizes the thesis and draws conclusions upon the data. It also recommends areas for further research. In the Appendix, redacted interviews of all thirty NFL players are included.