The JTA ran this feature on Dmitiry Salita and Yuri Foreman, two boxers who represent the return to prominence of jews in the ring.
Both are Orthodox and, as such, do not fight on Shabbat, which has lead to logistical problems along their careers, including scheduling high-profile events. Salita, in fact, has been criticized for padding his impressive record (both fighters are undefeated) by taking on opponents of dubious quality.
According to the article, “Salita acknowledges that he hasn’t fought top contenders, but he attributes it to bad luck. Every time he was scheduled to fight a major contender, the match fell through for one reason or another, he said.”