The 32-year-old has missed the Super Eagles' last seven games, including five qualifying matches for the continental showpiece in Egypt.
Following a meeting with the German tactician, Mikel disclosed his readiness for his fourth appearance in Africa's foremost football competition.
“I met with coach Rohr and we discussed his plans for the team in the forthcoming tournament. All I can say is that I am delighted and happy because I am coming to the Nations Cup” Mikel told Aoifootball.
Mikel was impressive for Middlesbrough in the second part of the 2018-19 season even though his contribution was not enough to earn The Boro a playoff spot.
He will now shift his focus to Nigeria's campaign in Egypt as they aim for a fourth continental title.
The Super Eagles are up against Madagascar, Burundi and Guinea in Group B.