Washington Redskins quarterback Robert Griffin III has claimed that he has been "hit" more often than usual in his last two matches.

Griffin had surgery last summer to try to cure a knee problem, but there are fears that taking continual blows could significantly shorten his NFL career.

He told CSN Washington: "I got two good shots there in the Minnesota Vikings game that I can avoid, [and I have to] take it on my part to make sure that it doesn't happen.

"We have just got to improve there and make sure we keep our quarterback upright. It takes all of us as a unit. So, yeah, I've been hit a bunch the past two games and everyone knows it, but we just have to move on.

"You don't want to be hit that much, and a lot of the great quarterbacks don't get hit that much. A lot of things go into that and you've got to get better."

Griffin took eight hard knocks to his frame during the match with the Vikings last Thursday.