Players who will find it difficult to qualify:
David Goffin: 2285 points

Belgium’s David Goffin would feel extremely hard done with the unfortunate injury he picked up during theFrench Open which ruled him out of action till after the Wimbledon. He lost a lot of points due to this and now finds himself in a rather tough spot.
However, he is back in form and will be looking to help his country win the Davis Cup this year. He might skip a tournament or two in order to prepare for the World Cup of tennis and in doing so, might miss out on qualifying for the tour finals.
He currently has 2285 points to his name and quite a few points to defend from last year.
Tomas Berdych: 2005 points

He was a constant in the Top 8 for many years but the 32-year-old Czech is not the player he once was. He has produced some noteworthy performances this year showing what he is truly made of. He reached the semifinals of Wimbledon this year where he lost to Federer.
With 2005 points in his kitty, he will have to surely win a Masters and another tournament or two in order to qualify for the finals.
Nick Kyrgios: 1700 points

On one hand, the supremely talented 22 year old has produced some magic on the court this year. Unfortunately, on the other hand, he has produced equally poor performances as well. He has been in the news due to his attitude on the court and has been fined on a number of occasions for the same.
However, he looks rejuvenated after the US Open and if the Laver Cup is anything to go by, he could be the one to look out for, for the rest of the season. He can demolish any opponent on his day and go on to achieve great things in his career.
He has only 1700 points to his name but given the fact that he hardly has any points to defend, he could be the surprise entry into the top 8 for the tour finals.
Milos Raonic: 1805 points

Last year’s Wimbledon finalist had a forgetful year and faced constant injuries which kept him out of many tournaments.
His best result was reaching the Wimbledon quarter-finals where he lost to Federer in straight sets.
Currently, on 1805 points, Raonic will have to put in a lot of effort in order to make the cut for the final showdown in London. He also has quite a few points to defend from last year.
Who Are Roger Federer's Kids? Know All About Federer's Twins