The undefeated Kansas City Chiefs are close to getting a key player back in the fold.

Kansas City is opening the 21-day practice window for running back Isiah Pacheco, who has been on injured reserve since fracturing his fibula back in Week 2.

Head coach Andy Reid announced that Pacheco and pass-rusher Charles Omenihu will both have their practice windows opened Wednesday.

Neither Pacheco nor Omenihu are expected to play this week against the Buffalo Bills.

They will be gradually ramping up football activities.

Kansas City’s starting running back since his rookie season, Pacheco played an integral role in the Chiefs’ two recent Super Bowl wins. He gained over 1,000 all-purpose yards as a rookie while helping Kansas City defeat the Eagles in that year’s Super Bowl.

Last year, Pacheco had an even bigger impact during the regular season, rushing for nearly 1,000 yards and scoring nine touchdowns. He then led the NFL with 313 rushing yards during the postseason as Kansas City successfully defended its title.

While his presence has been missed, the Chiefs’ offense has done an adequate job with Pacheco out of the lineup.

A big reason why was the free agent pickup of Kareem Hunt, who as a rookie led the NFL in rushing as a member of the Chiefs.

Hunt currently leads Kansas City with 449 yards and five touchdowns on the ground.

Sunday’s game is a big one for the Chiefs.

In addition to it being against the rival Buffalo Bills, Kansas City would join the 1990 49ers as the only back-to-back champions to start 10-0 if they can win Sunday.