At 8-0 on the season, things really couldn't be going much better for the defending champion New England Patriots. They are one of three remaining undefeated teams in the NFL and seem to be the favorites to hoist a second consecutive Lombardi. 

Despite all this, there has to be some concern over the injury running back Dion Lewis suffered in New England's 27-10 win over the Washington Redskins on Sunday. 

Lewis exited the game with a non-contact knee injury in the third quarter and did not return to action. After some time down on the turf, Lewis was able to walk off under his own power. That's really the only good news here. 

ESPN's Adam Schefter reported Sunday evening that there is no swelling in the knee. Though, there is some concern over the ACL being "loose," which is an indication there could be some structural damage. 

Patriots RB Dion Lewis scheduled to undergo MRI on his knee. No swelling yet, a good sign. ACL loose, a bad sign. MRI to tell full story.

— Adam Schefter (@AdamSchefter) November 8, 2015

Lewis is slated to undergo an MRI. 

The unheralded running back from Pitt entered Sunday's game with 569 total yards and four touchdowns in five games on the season.