James Cook doesn't appear satisfied, nor should he. The Buffalo Bills' dynamic running back is coming off his most-fruitful season yet, but the ultimate goal still has not been reached.After Cook led all NFL players with 1,621 yards rushing during the regular season, the Bills came up three points short against the Denver Broncos on the road in the AFC Divisional Round.The ending put a damper on an historic season for Buffalo's primary ball carrier, who became the franchise's first league rushing champion since the late Hall-of-Famer OJ Simpson one-half century ago."I mean, it [winning the rushing title] was good, but the ultimate goal is to win a championship. And that didn't happen," said Cook, who addressed reporters during last week's minicamp in Orchard Park.While Cook totaled 141 yards from scrimmage on 26 touches during the overtime loss to the Broncos, he failed to record a touchdown and his costly fumble eliminated a prime first-half scoring chance.Jan 17, 2026; Denver, CO, USA; Buffalo Bills running back James Cook III (4) reacts after losing an AFC Divisional Round playoff game against the Denver Broncos | Ron Chenoy-Imagn ImagesImproving ball securityBall security is the one area where Cook has proven vulnerable beginning with his first-ever NFL touch against the Los Angeles Rams in 2022.This past regular season, Cook put the ball on the ground six times with the Bills losing three of those fumbles.“Just protect the ball, most importantly," said Cook prior to summer break. "I didn't feel like I did good enough job of that, but new season, [I] got the whole offseason to work on [it], and got the summer, so come back ready to go."While Cook wasn't present for the voluntary portion of Organized Team Actvities (OTAs), he was apparently following an intense workout regimen at home in South Florida. Bills' first-year head coach Joe Brady recognized the running back's committment and work ethic during a press conference earlier this month.Jan 11, 2026; Jacksonville, FL, USA; Buffalo Bills running back James Cook III (4) runs with the ball short of the end zone during the first half against the Jacksonville Jaguars in an AFC Wild Card Round game at EverBank Stadium. | Nathan Ray Seebeck-Imagn ImagesSuper Bowl caliber running gameWhile quarterback Josh Allen, a five-time NFL MVP finalist, is certainly a factor in the ground game, Cook has developed into a bellcow for one of the league's most-productive rushing offenses.Improving his yards per carry average all three seasons as a starter, Cook handled his heaviest workload yet in 2025. He ran the ball 309 times for the NFL's top-ranked rushing attack, carrying the ball more than any Bills' player since Willis McGahee's 325 attempts in 2005.In a Bills On SI exclusive one-on-one interview last summer, Hall-of-Fame running back Thurman Thomas paid Cook the ultimate compliment stemming from his remarkable performance in the 2024 AFC Championship Game.Jan 26, 2025; Kansas City, MO, USA; Buffalo Bills running back James Cook (4) dives for a touchdown against the Kansas City Chiefs in the AFC Championship Game | Denny Medley-Imagn ImagesThat is the furthest that Cook's been in the playoffs, and the goal is to change that in 2026."You just got to go back to the drawing board and get better and see what's the future holds for this year," said Cook, who has been to three straight Pro Bowls.Until the future includes hoisting the Lombardi Trophy, don't expect the NFL rushing champion to be satisfied.Add us as a preferred source on GoogleFollow