Keane, 23, who has played for England at under-19, under-20 and under-21 levels, will report to St George's Park on Tuesday with the rest of the squad.
Gareth Southgate called him up after Johnson was ruled out of Saturday's World Cup qualifier against Malta.
On Monday, Andros Townsend replaced the injured Raheem Sterling in the squad.
Crystal Palace's Townsend, 25, has played 11 times for his country and scored three goals, but was not selected for Euro 2016.
He has played in all seven of Palace's Premier League games since joining from Newcastle for £13m in the summer.
England, led by interim manager Southgate, face Malta on 8 October and Slovenia three days later.
No details have yet been given on Manchester City player Sterling's injury.
Keane has featured in all of Burnley's Premier League games this term.
Between 2013 and 2016, the former Manchester United trainee made 16 appearances for the under-21s side under Southgate.
Goalkeepers: Fraser Forster (Southampton), Joe Hart (Torino, on loan from Manchester City), Tom Heaton (Burnley)
Defenders: Ryan Bertrand (Southampton), Gary Cahill (Chelsea), Phil Jagielka (Everton), Michael Keane (Burnley), Danny Rose (Tottenham), Chris Smalling (Manchester United), John Stones (Manchester City), Kyle Walker (Tottenham)
Midfielders: Eric Dier (Tottenham), Jordan Henderson (Liverpool), Alex Oxlade-Chamberlain (Arsenal), Michail Antonio (West Ham), Jesse Lingard (Manchester United), Theo Walcott (Arsenal), Dele Alli (Tottenham), Andros Townsend (Crystal Palace)
Strikers: Wayne Rooney (Manchester United), Marcus Rashford (Manchester United), Daniel Sturridge (Liverpool), Jamie Vardy (Leicester)

They had previously hoped to have a deal for the Championship club, who are in administration for the third time in four years, agreed by Friday.
The Bulls said in a statement "it had not been possible to complete the due diligence in the time available" but work would continue over the weekend.
Joint administrator Gary Pettit asked fans to "remain patient".
He added: "My legal team and my colleagues will continue to work hard over the weekend to give every prospect of success for the survival and renaissance of Bradford Bulls.
"Obviously, we wish to end the uncertainty for all concerned as quickly as is possible. We recognise and understand the human aspects for everyone (and their families) who has the best interests of Bradford Bulls at heart.
"I would reiterate that it is crucial we obtain the right deal - rather than the quickest deal - for the club's future."

Thousands of pounds were allegedly stolen when security guards were targeted at the Hatfield Avenue Shell garage in Fleetwood on Wednesday.
An axe was said to have been thrown at a police car during the raid, while a woman was dragged out of her vehicle.
Four men from the Bolton area, aged 22, 24, 27 and 32, have been charged with two counts of robbery.
They were also charged with dangerous driving and threatening a person in a public place with a bladed or pointed article.
They are due before Blackpool magistrates later.

Straker, 27, has been without a club since leaving York in January, where he made 27 appearances.
He began his career at Crystal Palace and helped Aldershot Town win the Conference title in 2008, before moving to Southend United.
Grimsby are currently third in the National League, having lost only one game in the league since October.
Burnley defender Michael Keane has been handed his first international call-up after Stoke's Glen Johnson withdrew from the England squad through injury.
[NEXT_CONCEPT]
The joint administrators of Bradford Bulls have extended the deadline to buy the club to Monday, 19 December.
[NEXT_CONCEPT]
Four men have been charged in connection with a robbery at a Lancashire petrol station.
[NEXT_CONCEPT]
Grimsby Town have signed former York City midfielder Anthony Straker on a deal until the end of the season.