Ibrahimovic, 35, has bagged 17 league goals in his first season in England, having joined United from Paris St Germain at the start of the campaign.
He said: "There are better players now and it's a better standard".
If Kane or Alli win the award this term the north Londoners will have provided the victor for five out of the last six seasons.
Belgian striker Lukaku was eligible for both awards as the Young Player gong is open to those aged 23 or under at the start of the season.
Kante, meanwhile, has bolstered Antonio Conte's midfield and transformed Chelsea into title contenders after the France star won the Premier League with Leicester City last season.
The winners will be announced at the PFA Awards ceremony in London on Sunday April 24.
Michael Keane, Leroy Sane and Jordan Pickford are up for the young player of the year award, alongside 2016 victor Dele Alli.
N'GOLO KANTE Club: Chelsea Age: 26 Key stat: Has played every minute in the league this season apart from Boxing Day against Bournemouth, when he was suspended, and the final 11 minutes against Tottenham on January 4.
The Daily Mirror picked out six names they believe should be on the list, based on their superior performances in certain aspects of the game.
As the season draws towards its climax, the PFA Awards is a celebration of the achievement of all PFA members from the last 12 months.
Harry Kane and Dele Alli have both received nominations for the Professional Footballers' Association awards. Weir is again nominated, along with Birmingham's Jess Carter.
Eric Cantona became the first recipient of the senior men's award from outside the United Kingdom and Ireland when he was voted the top player by his peers in 1994.
"I don't see Hazard playing every weekend, even though I know he is one of the best".