Jonathan Allen is in jeopardy of missing some significant time this month.
The Redskins' third-year defensive end is considered "week to week" after suffering a knee sprain in Sunday’s 32-27 loss to the Eagles, coach Jay Gruden announced.
Allen took to Twitter after the game to assure fans he was "going to be fine."
My knees going to be fine, just a sprain!!
— Jonathan Allen (@jonallen93_) September 9, 2019
According to NFL Media, which cited an unidentified source, Allen is believed to have suffered an MCL sprain but is set to have an MRI exam Monday to determine the severity of the injury and more specific recovery timetable.
An MCL sprain can typically take up to six weeks to heal.
Allen, who was named a defensive captain before Sunday's game, exited the game in the first quarter and was visibly frustrated as he slammed his helmet to the ground as he walked off the field to the medical tent.
Gruden later clarified that Allen was held out as a precaution to avoid aggravating the injury.
"He was out there walking around pretty good," Gruden said. "We thought the risk was a little bit too great right now with it being a fresh injury."
Allen, 24, was selected by Washington with the No. 17 overall pick of the 2017 draft and has quickly become one of the Redskins' core defensive players.
He previously missed 11 games his rookie season with a foot sprain.
The Redskins are slated to host the Cowboys in Week 2 action.