Game-day performance in the National Football League is scrutinized in a thousand different ways. But when this season ends, Russell Wilson, the star quarterback for the Seattle Seahawks, may well be judged by an unusual metric: whether his public declaration of celibacy affected his on-field play.

Mr. Wilson is dating the singer Ciara Princess Harris (known as Ciara), and before the season began news broke that the couple are abstaining from premarital sex. As Mr. Wilson publicly told Miles McPherson, the pastor of the Rock Church in San Diego, he and Ciara were backstage in her dressing room one night when they agreed to conduct their relationship “Jesus’ way.”

Mr. Wilson, who was previously married (and won a Super Bowl with the Seahawks after the 2013 season), asked people to pray for him, given the sex appeal of Ciara, whose songs include “Dance Like We’re Making Love,” “Body Party” and “Love Sex Magic.”

