Captain Alastair Cook confirmed the 24-year-old would come in at first drop in the first Investec Test, with Ian Bell and Joe Root set to follow in the middle order.
When England last played the longer format, the fifth and final Test of the Ashes whitewash in Australia, Ballance batted at five in the first innings, due to a nightwatchman, and four in the second knock.
Bell, a veteran of 98 Tests, went in ahead of him on both occasions but will not now take over the role held for several years by his Warwickshire colleague Jonathan Trott.
Cook, who will open alongside debutant Sam Robson, was untypically ready to confirm the make-up of the top six – a move that would have been anathema under the secretive reign of previous head coach Andy Flower.
Asked where Ballance would bat, Cook said: “Gary will bat at three, Belly at four, Rooty at five and Mo [Moeen Ali] at six.”
As well as clarifying the batting order, Cook effectively confirmed the team, with Chris Woakes the likely odd man out.
After years of guarding even the most obvious facts under Flower, Cook’s eve-of-match admission rang true with new head coach Peter Moores’ change of style.
The series is set to get under way with emotions still high about Jos Buttler’s “Mankad” dismissal in the one-day international at Edgbaston.
England’s wicketkeeper was run out backing up at the non-striker’s end by Sachithra Senanayake having twice been warned for leaving his ground. It was a legal but controversial mode of dismissal, infuriating England and their fans.
Cook spoke in measured tones about the incident ahead, however he could not hide the fact that it will add spice to the encounter.
“Both sides will play a particularly hard game of cricket, but we have a responsibility to do it in the right way,” he said. “There will be a lot of people watching us, a lot of kids as well, but they want to see tough cricket.
“What happened last week. . . I was quite emotive about it, but I’ve settled a bit.
“It was frustrating at the time and it still is...but he [Senanayake] was in his right to do it. The bottom line is you can’t really argue against it.”
Sri Lanka skipper Angelo Mathews was strident when asked about the Buttler run out.
The all-rounder is content his side acted within the rules and simply punished Buttler for seeking to steal an advantage. “Buttler was warned a few times,” said Mathews. “We analysed the Lord’s ODI and they had taken 21 twos in the last ten overs.
“He was backing away [backing up] and we did nothing about, but we couldn’t let him do that every game.
“We warned him twice. There is a law and if you’re going to judge the captain of the other team [for using it] there shouldn’t be a law. If that’s the case it should be taken out.
“We played within the rules and stuck to the spirit of cricket, but we shouldn’t let anyone take advantage of us.”