Eddie Jones insists "second-season syndrome" explains Maro Itoje's slide in form since last summer's British and Irish Lions tour.

In between making his debut against Italy two years ago and helping the Lions record a drawn Test series against New Zealand, the England lock's international career was an unqualified success that included a world player of the year nomination.

He was used sparingly during the autumn and - having subsequently recovered from a fractured jaw - he has struggled to make an impact after three rounds of the 2018 NatWest 6 Nations title defence.

While Jones has pointed out that the nation which supplies most players to a Lions tour traditionally labours through the next season, he believes there is a different source for Itoje hitting a plateau.

"Maro is second-season syndrome. First season, no one knows what's your best shot, no one knows where you score runs," Jones said.

"Second season, everyone knows and they take that away from you. And you've got to find a different way to score runs. That's what he's finding at the moment.

"It's a great exercise for him, because by the time he gets to the World Cup he'll be in his third year.

"He is going to be a great player for us. What he's going through at the moment is very natural."

Jones believes opponents have found a way to nullify Itoje's presence at the heart of the forward battle, but is backing the 23-year-old to emerge stronger from an experience that he believes is drawing the best from him.

"Maro is an energetic player who gets a lot of his energy from around the ruck, but he is just not being given that opportunity," Jones said.

"He is a very diligent and serious player. I have been really impressed by him. He has done remarkably well.

"In fact, I am more impressed by him this season than I was last season because he is working hard to improve his game, he understands he has to improve his game.

"He has to work it out himself but the coaches assist him in steering him in one direction to prioritise his time and effort.

"A lot of players get stuck in second-season syndrome. It's difficult, particularly when you come out of the blocks in the first season because you not only carry the expectation, you carry more attention from other players."

England head to Paris for Saturday's match against France with their title defence delicately poised following a 25-13 defeat to Scotland that has placed Ireland at the forefront of the chase for supremacy in Europe.

"History shows that the team that has the most Lions struggles in the Six Nations," Jones said.

"There's a lot of reasons to understand why. We had 16 players on the Lions tour. I always knew this was going to be a tough year, but we haven't used that as an excuse and we don't intend to.

"We've had to manage players differently, we've had to train players differently. We're getting to the end of it now. I'm starting to see some light about where the players can be.

"But certainly, you've got that many players playing a post-season tour - that is three or four times longer than a normal tour - and it's going to have an effect."