In an interview to The Week magazine, Chappell said the road ahead was tough for Munaf, Sehwag and Irfan Pathan as they battle fitness issues and form slump.
''Irfan and Munaf have been and will be important. I can't predict whether they will be in the World Cup squad, but they are definitely in the mix. Unfortunately, Sehwag and Munaf don't have enough cricket to force their way back,'' Chappell said.
Asked about the way forward for the out-of-favour players, Chappell said the trio has to get in form for making a case for selection.
''It will be based on the contributions they can make and their form, fitness and attitude. If all the four, including Anil Kumble, are fit and in form, they will be in the side,'' he explained.
Speaking about Pathan, who was dropped from the side in the middle of the Test series against South Africa after an alarming slump in his bowling form, Chappell said the seamer just needed a good spell to be back in the groove.
''This is not the first time he has been out of the team or out of form. He is not on the edge. He is in good batting form and is only a few good overs away from regaining his form with the ball,'' the Aussie explained.
Chappell said apart from this, the fitness of Yuvraj Singh was also a major concern as the Punjab-player is a middle-order mainstay and crucial to India's World Cup chances.
''To do well in the World Cup, we want him to be fit. Someone like him can make a difference in the middle overs,'' he said.
The search for a genuine all-rounder also continues and Chappell said he was looking at Suresh Raina to take over the responsibility.
''We need flexibility. Suresh Raina can be a useful all-rounder but it doesn't mean he will be a match-winner with the bat and the ball, but will do the job,'' Chappell said.
Describing the ongoing-series against West Indies and the upcoming against Sri Lanka as the final lap before the World Cup, Chappell said India were well on track to achieving the winning squad for the coveted trophy, which would involve making some tough decisions.
''...it is the home run and the World Cup will be on us before we know it. It is improtant to try and come up with the best combination. We have a few more games and we should try and win them so that we get some confidence before the World Cup,'' he said.
''We have to be fairly cold and calculating in making decisions and base them on facts not fiction...on knowledge and experience not whether media or general public is going to like it,'' he added.
Asked about the most troublesome area in India's game, Chappell said the Men in Blue could do with some overall improvement but fielding is one aspect which needs to be worked hard upon.
''We can bat better, bowl better and field better. We are not going to be the best fielding side in the World Cup but need to be a safe one. We should improve the running between the wickets,'' he said.