Justin Fields has always been an intriguing fantasy football quarterback due to his elite rushing upside. The 2025 NFL season could result in a significant increase in his overall value compared to last year. He switched teams from the Pittsburgh Steelers to the New York Jets, where he is expected to be locked in as their starter.His situation may have drastically changed during the second day of Jets training camp after Fields was reportedly carted to the locker room with a lower leg injury. He was apparently able to walk off the field before getting in the cart, which is encouraging, but this is still concerning news for his outlook this year.The hope for the Jets is obviously a minor injury situation, but for a quarterback who relies so heavily on their legs as a part of their overall game, this could negatively impact his fantasy value, even if he can get back on the field. Across just 50 career games, Fields has rushed for 2,509 yards and 19 touchdowns, so his outlook is contingent upon his mobility.Before the injury, Justin Fields profiled as a potential starting quarterback for many fantasy football teams this year, as a back-end QB1 or elite QB2 option for most rosters. He has become much riskier with the recent injury news, and if it impacts his rushing ability, his value will take a massive hit.The best approach for Fields at the moment is to closely follow his injury updates before drafting him. For managers who must draft prior to getting more clarity on the situation, having a strong backup will be essential. If targeting Fields in drafts right now, another reliable quarterback should also be selected as an alternative in case Fields is limited or unavailable this season.Potential replacements for Justin Fields in fantasy footballJustin FieldsWhile it's still relatively early in the offseason, some fantasy football leagues may have already conducted their drafts. This means that several managers are probably already counting on Justin Fields to be their quarterback this season.Managers in this situation who didn't draft a solid backup should quickly go to the waiver wire to add another quarterback. Some of the potential options that could be available include Cam Ward, Russell Wilson and Geno Smith. Ward offers the most upside, but also the most risk, while Smith is among the most reliable alternates given his current situation with the Las Vegas Raiders this year.