Billy Vunipola has warned that ­professional club rugby is in danger of becoming like the NFL in the United States, with players hiding injuries from their coaches in order to win new contracts.

Vunipola claims it is a widespread problem and admits to putting his own body at risk by failing to fully declare his physical condition to his coaches at Saracens.

The 25-year-old returns to the Saracens starting line-up on Saturday for the Gallagher Premiership fixture against Northampton at Franklin’s Gardens.

It will be his first start since he broke his right arm for the second time this year during England’s tour of South Africa in June.

He was limited to just seven games for Saracens and two for England last year because of ­successive shoulder, knee and arm injuries, and the lengthy rehabilitation time has given the England No8 cause for reflection.

Vunipola admits in the past he ­allowed his “ego dictate what my body’s telling me”, leaving him vulnerable to further injuries, admitting he had previously done so “easily 10 times” at Saracens.

View more!

Yet it was not just his pride that determined his recklessness but also a feeling of insecurity; a fear of generating a perception that he was a shirker who was only interested in playing in big games and living off his reputation.

“I got to the stage where I wasn’t doing [commercial] appearances at Twickenham [while he was injured] because I felt embarrassed. It was like people would be, “Oh, this guy is living off two years of his work’,” Vunipola said.

“I know no one was thinking that, they just wanted to see me happy, but that was my mindset and that translated over to training and playing.

“My friends probably think I’m taking the mick out of them, just so I can play all the big games, but now I’m more confident in myself to say it.

“I know people will read it and think, ‘Oh, he’s silly’, but that’s truly how I felt and now I am comfortable knowing that when I am ready I will play and when I am not I will flag it.”

View more!

Vunipola highlights his return from a lengthy knee injury against Wasps in January as one of those moments when he knew he was not ready to play; a week later he broke an arm against the Ospreys.

“I think I got to a stage where I was just trying to be a hero, putting myself in situations where I was vulnerable,” he added. “For example, I came back against Wasps, maybe it wasn’t the smartest idea from my point of view to tell the coaches that I was ready, it was almost like trying to show them I am tough when I wasn’t, and it’s no one’s fault but mine.

“I was almost showing a mask that wasn’t me but now I’m just up front with everything – if I’m sore, I’m sore – not letting my ego dictate what my body’s telling me.

“If I had been smarter when I went into the tackle, I would have been fine, but I was trying to impact the game.

“I’ve learnt a lot and hopefully now I can just get a good run of games.”

This season is different. His return to play has been graduated, with an appearance off the bench in the victory over Bristol last week.

Yet if he has come to terms with the issue, he worries that others are putting themselves at risk by ­continuing to play beyond the pain barrier.

“It’s tough… I can tell you a lot of people still have injuries and try to hide it,” said Vunipola.

“We saw it with the high turnover of players being released, it’s almost like we’re into NFL territory.

“Not yet, but we’re getting to a stage where competition for places is really hard and you can still have players masking pain, trying to earn that extra contract.

“That’s something that’s always in the back of my mind. For me the biggest thing was, ‘Do the coaches or the players think that I’m taking them for a ride?’

“That’s why I never wanted to say no if I was sore – that was my mindset, no one else’s, but I’ve learnt now I have just got to be up front.”

Vunipola is one of the most explosive ball carriers in world rugby and his absence was acutely felt by both club and country last year, but his change in mindset has included a reassessment of how he plays the game, too.

“It is about trying to divert teams to thinking I am going to carry in the same position and then we ­attack in a different way, using my potential threat to divert defenders away,” added Vunipola, who is wearing an arm guard this season for added protection.

“Also not always trying to ‘jackal’ [at the breakdown], that’s something I always used to try to do. That’s something I have suffered from, trying to jackal all the time. And not knowing the damage it does to you. It’s about just picking my moments better.

“I have thoughts in my head that people doubt me so I have to go the extra mile but now I’m less insecure about myself. But I think those insecurities make me who I am as a player. It drives me to be as good as I can be.”