Derrius Guice is tended to after getting hurt during Thursday’s preseason game against the New England Patriots. (Photo by John McDonnell/The Washington Post)

The Washington Redskins have officially placed rookie running back Derrius Guice on injured reserve.

Shortly before the roster move was announced Saturday, Coach Jay Gruden confirmed the obvious: Losing Guice is a significant blow, not only for the promising rookie, but also for the Washington Redskins’ seemingly improved offense.

“We were obviously very upset for Derrius,” Gruden said a day after an MRI revealed the Redskins’ second-round pick tore the anterior cruciate ligament in his left knee during Thursday night’s preseason loss in New England. “He’s put a lot of work in, had a very promising rookie season ahead of him, but unfortunately, these injuries happen.”

The team officially placed Guice on injured reserve, along with tight end Manasseh Garner, who also tore an ACL against the Patriots.

“He’s a great kid, he’s going to work hard, he’ll recover. So there’s no problem there,” Gruden said of Guice. “We’re just disappointed for Derrius. We had high hopes him, what he would do for this football team and what he would have accomplished his rookie year as a person and all that good stuff. But knowing him and knowing the doctors we have and the rehab that we’re going to provide for him, he’ll be 100 percent in no time.”

It’ll be difficult for the Redskins to replace Guice’s playmaking ability in the running and passing game, but Gruden said the team has no plans at this time to sign a veteran back, adding: “I think we’re pretty good at the running back spot.”

Injury updates: Matt Ioannidis, who left the Patriots early due to injury, is week-to-week with a sprained ankle and a slight knee strain. Gruden said he doesn’t expect the veteran defensive end to participate in this week’s joint practices with the Jets or play in Thursday night’s game at FedEx Field. … First-round pick Daron Payne (ankle) will practice, according to Gruden, but it’s unclear if the rookie nose tackle will play against the Jets Thursday night. …Rookie wide receiver Trey Quinn checked out fine and will attempt to practice today.

Additional roster moves: The Redskins also signed the following free agents: tight end J.P. Holtz, linebacker Jeff Knox and defensive lineman Jalen Wilkerson. … They waived fullback Elijah Wellman