UPDATE (2:58 p.m. ET): Derrius Guice’s knee injury is much worse than initially reported.

The Washington Redskins running back suffered a torn ACL in Thursday night’s preseason game against the New England Patriots, NFL Media’s Ian Rapoport reported Friday afternoon.

The team confirmed Guice will miss the entire 2018 season.

ORIGINAL STORY: It appears not all is well with Derrius Guice after his NFL preseason debut Thursday night.

The Washington Redskins rookie running back has been initially diagnosed with a sprained MCL, NFL Media’s Ian Rapoport reported Friday morning.

Per Rapoport, Guice will undergo an MRI to confirm the injury, which he suffered late in the first quarter of Washington’s preseason game against the New England Patriots on a 34-yard run that was called back due to a penalty.

Guice’s knee appeared to twist awkwardly as he fell to the ground, and many feared the injury would be serious. But the 21-year-old LSU product downplayed the ailment after the game, telling NBC Sports’ JP Finlay “all is well” when asked about his knee.

Guice’s timetable for a return is unclear, but it’s likely he’ll miss the Redskins’ next preseason game and could be held out for the rest of the preseason as a precautionary measure.

The 59th overall pick in the 2018 NFL Draft has high expectations entering his rookie season and likely will be Washington’s lead back on early downs. Guice currently is listed as the No. 23 running back in NESN.com’s fantasy football rankings and sits at No. 41 in the Top 100.

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