Casemiro was one of Man United's key players during the 2022-23 campaign, contributing seven goals and seven assists in 51 competitive matches.
The Brazilian has continued to be a regular fixture this term, having started 30 of his 31 appearances in all competitions.
However, Casemiro has seen some of his performances come under scrutiny this season, including his recent displays as a makeshift centre-back.
Having drawn criticism during the campaign, Casemiro has been linked with a summer departure despite being under contract until at least June 2026.
Casemiro is believed to be attracting interest from Saudi Pro League club Al-Nassr, who are seemingly keen to reunite him with his former Real Madrid and Man United teammate Cristiano Ronaldo.
Casemiro insists he can still compete in Premier League
While he appears to be heading towards the exit door, the 32-year-old has hinted he could remain at Old Trafford, insisting he still has the "energy" and "mentality" to play in the Premier League.
"I feel very well, very well," Casemiro told Sky Sports. "I'm really well, I feel healthy, with energy and the same mentality I always had.
"I guess people end up talking about the age factor, but it's been proven. Recently, our friend Thiago Silva, at the age of 39 coming here and showing that, yes, you can play. The previous Ballon d'Or winners were over 34.
"At Manchester City, there's Kevin De Bruyne. Mohamed Salah at Liverpool. I think age is not an issue, it is not a factor in this, but analysing one's game and knowing about everything that is happening around the game."
"These are people who analyse football well, who see what's happening, who know what's happening, analysing not the age. But I'm well, I'm happy, living every day I get to play here. As I usually say, Manchester United gave me what I wanted.
"This joy of being able to enjoy the game, enjoy the Premier League. So, I'm happy to be here at Manchester United and enjoying the game."
Injuries key to Man United's struggles
Man United have experienced a difficult campaign, crashing out of the Champions League group stage and falling short of last season's top-four finish.
Having collected 57 points from 37 games, the Red Devils enter the final day in eighth place and are at risk of missing out on European qualification via their league position.
Casemiro believes a significant number of injury issues have been one of the main factors behind Man United's tumultuous campaign.
"We had I think over 60, 70 injuries," Casemiro added. "I've never seen this in my life. And, without a doubt, my season, it's far from being the best, but I had a big injury, which was going to keep me away initially for a month and a half. That changed to three months.
"I came back, felt something again. The past five, six matches, playing as a centre-back because we didn't have other players for that position. So, I played there, kind of trying to cover a hole where we didn't have players available.
"When you have 60, 70 injuries, it is hard. It is hard to win, it is hard to think about winning a Premier League. You have so many injuries, of important players, players that you think will be able to play throughout the season, and you can't count on them."
Despite their struggles this season, Man United will still have the chance to claim a piece of silverware when they face rivals Manchester City in the FA Cup final next weekend.