An X-factor is generally defined as something or someone that has a possesses a strong influence but can be unpredictable in nature. As it relates to the NFL, an X-factor can be a player that is influential in how a team will perform but they’re predictability or reliability is volatile.
A team can have several different X-factors, but some players can have more influential role than others. For the Baltimore Ravens, is starting left tackle Ronnie Stanley the team’s biggest X-factor in 2025?
An ESPN ranking of the league’s top rosters recently listed Stanley as such, citing his injury history and risk of potentially missing games.