The team under Virat Kohli continue to fret over the slot after a series of candidates fluffed their auditions before they fly to England seeking a third ODI World Cup crown.
All-rounder Vijay Shankar is expected to bat at number four while they have another option in back-up opener Lokesh Rahul but Kapil, the captain of India's 1983 World Cup winning team, said batting order demarcation had blurred.
"In the age of Twenty20, it's difficult to say who's an opener and who's number four," Kapil told reporters at a promotional event.
"The mindset these days is anybody can go and bat (at any number). Remember when (Mahendra Singh) Dhoni went before Yuvraj Singh in Mumbai?" he said, referring to the 2011 final in which India beat Sri Lanka to win their second 50-over title.
"In the last 10 years cricket has changed so much that it almost feels odd to have permanent slots, maybe with the exception of openers.
"In fact, these days you can even send an opener to bat at number four."
Kapil picked India, holders Australia and hosts England as the top three teams likely to make the semi-finals with one team from New Zealand, Pakistan and West Indies completing the line up.
Considered the greatest all-rounder India has produced, Kapil said the team under Kohli had the right mix of youth and experience and the balance needed to win the tournament.
He has high hopes from Hardik Pandya, often touted as the 'next Kapil Dev', but insisted the seam-bowling all-rounder should be allowed to play freely.
"Don't put pressure on him. Let him play his natural game with a free mind, rather than bogging him down with comparison. I don't like anybody being compared to anyone."
(Reporting by Amlan Chakraborty in New Delhi; editing by Sudipto Ganguly)
