The pair were in the same class at school and were friends outside the classroom when growing up in Country Durham.
Roberts, 24, was found at his home in Northants on Tuesday afternoon. Police are not treating his death as suspicious.
Tribute: Johnson (left) will dedicate his next performance to Roberts
Johnson, 23, said: 'I'm absolutely devastated about Dale's passing. He was a really good friend.
'I grew up with Dale. We were in the same class at school and also played at Middlesbrough together. His parents are friends with my parents and we often went on holiday together.
Will be missed: Dale Roberts
'I know he was so desperate to improve and get up the leagues, he was a really good keeper, too. My heart goes out to his family and friends and I will really miss him.'
While the England winger broke into the Middlesbrough first team before earning a £6million move to Manchester City earlier this year, while Roberts left Boro to join Nottingham Forest in 2005 and had a series of loan spells before joining non-League Rushden.
Johnson will pay a personal tribute to his friend if deployed for City against Juventus in the Europa League on Thursday evening, saying: 'I am going to play in honour of Dale and dedicate my performance and hopefully a victory to his memory.'
Roberts' fiancee and parents issued statements speaking of their devastation on Wednesday night.
His fiancee Lindsey Cowan, described the 24-year-old as 'my childhood sweetheart and the love of my life'.
Tragedy as Rushden goalkeeper Roberts dies suddenly at the age of 24Click here for the latest Conference National results, fixtures, standings and more in our Stats Zone MANCHESTER CITY FC