"I am not yet fully fit to play," admitted the 24-year-old star to Guinean TV after Belgian coach Paul Put named his 23-man squad for the biennial African football showpiece.
"After training with the ball at Liverpool, I have arrived at the Guinean training camp in Morocco and am ready to train with the team.
"I want to reassure Guinean supporters, the coaches and the rest of the squad that I believe I will be ready for our first match."
Guinea, who have lost warm-up matches against the Gambia and Benin, launch their Group B campaign in Egypt against Madagascar on June 22, one day after the tournament kicks off.
Keita was injured playing for Liverpool against Barcelona in a UEFA Champions League semi-final last month and manager Jurgen Klopp said he would be sidelined for two months.
Guinea and three-time champions Nigeria are favoured to qualify for the knockout second round from a group completed by debutants Burundi and Madagascar.
Winners and runners-up from the six groups advance along with the best four third-place finishers in a competition expanded to 24 nations for the first time.
The Guineans came closest to winning the Cup of Nations in 1976, when they finished runners-up to Morocco after the only edition decided by a mini-league.
Meanwhile, Vincent Aboubakar, the forward who scored the goal that won the 2017 final for Cameroon, will not be going to Egypt amid doubts about his fitness.
He resumed training last month with Porto after a lengthy absence caused by a knee injury and Indomitable Lions coach Clarence Seedorf is not convinced he is match fit.
In his absence, Cameroon will look to the likes of in-form Villarreal forward Karl Toko Ekambi for goals as they seek back-to-back titles for a second time.
Aboubakar scored two minutes from time in Libreville two years ago to seal a 2-1 come-from-behind final triumph over record seven-time champions Egypt.
They should not experience too much difficulty qualifying from Group F, where they meet four-time champions Ghana and less formidable Benin and Guinea-Bissau.
Former Dutch star Seedorf has included 10 of the squad that emerged as shock 2017 champions, including Ekambi.
He also recalled 35-year-old Fenerbahce goalkeeper Idriss Carlos Kameni, who was not chosen for the last tournament.