The 23-year-old played through the pain barrier for the Magpies last season in order to help them achieve promotion. Once that was finally confirmed against Preston North End in April, Lascelles underwent surgery on his groin and missed the remaining two games of the season.
And because of playing whilst injured, United's captain believes he's a different player now. Lascelles is prepared for the upcoming season and believes his teammates are too.
Going under the knife
"For me, it needed to happen," said Lascelles.
"At the start, we didn’t know what it was. It was really hard for me, as the type of player I am, it’s about being physical and fast and using athleticism.
“If you take that away, which is what happened, I was struggling towards the end of the season.
"Obviously, I waited to the end of the season, and I’m glad I did and was a part of the team that went up.
“I’m a different player now. I feel a lot sharper. I can move about better. I’m glad I got that done."
Lascelles takes his side to Deepdale tomorrow afternoon after a week preparing in Ireland. He wants to maintain his sharpest and "push to get better fitness."
“There are no excuses now. I’m fit and strong. I’m ready to get started." he added.
Last time out - 2015/16
In Lascelles debut season at St James' Park, he endured the pain of relegation.
The former England U21 International broke his way into the first-team when Rafael Benitez came in for the final 10 games. Despite relegation, Lascelles became a big figure among players and fans, which all sterned from his brutally honest post-match interview after a 3-1 away defeat to Southampton in April 2015.
And with the club having to rebuild its squad last season, Lascelles is confident in the players Benitez has assented.
“It’s going to be completely different [to 2015-16],” said the Derby-born player.
“We’re focused and we’ve all got a goal. We’re a really tight group and we’re all talented.
"Hopefully, the manager can bring in a couple more players to strengthen the team.
“I’d be happy going into the Premier League with this team. Everyone’s disciplined and works hard and play for the badge. That’s what you need.”
Possible new defence partner
Newcastle signed Florian Lejeune from Eibar earlier this month. Lejeune adds competition to the United defence with Lascelles, Ciaran Clark and Chancel Mbemba all possibilities.
And with Benitez looking to stabilise his defence in the transfer market, Lascelles has been impressed with the manager's latest addition. He said: “He looks impressive. He’s a big boy. He’s pretty athletic and good on the ball."
“When he gets used to English football and the tempo, I think he’ll be a really good player for us. I think the manager’s done well in signing him. We’ll see what else happens. We’ve got a good team anyway.”