Dhoni said it was "a tempting and challenging decision" but he was likely to continue with three seam bowlers "because if you play with just two seamers, your bowling becomes quite similar".
India will deploy four specialist bowlers, plus a choice from its part-timers.
The pitch at the Chinnaswamy Stadium aided turn during a practice game against Australia last week and there has been speculation that India would play another spinner, apart from Harbhajan Singh, and just two pacers for the Group B game.
Ravichandran Ashwin and Piyush Chawla are the other specialist spinners while Yuvraj Singh and Yusuf Pathan are the part-time spinners used regularly by India.
"The wicket can definitely change a lot in two weeks, a lot depends on how rolling is done and how it is prepared," Dhoni said of the pitch, adding that rain could not be ruled out.
"We'll have to see the weather and pitch before the start of the game," he said.
The skipper said it was an important game, but that India's preparations had remained the same.
"In every game you have to start from scratch," he said. "You have to do all the good things that you did before, whether you are playing Bangladesh, England, Australia or Ireland."
Dhoni said there was no added pressure playing the first World Cup match at home.
"I made my debut in 2004. I've never played a series when we are not under pressure - whether it is to win a match easily or playing against a strong opponent. Most of the guys are used to it," he said.
"We have had a good start (to the tournament) but we are not celebrating yet."
Asked whether England batsman Kevin Pietersen's performance could prove crucial, Dhoni said there was no particular player in the England side who held the key to the match.
Dhoni added that there were no fitness worries in his team. Batsmen Virender Sehwag and Yuvraj, who had suffered minor injuries during practice sessions, are both fit.