Something happened before I was made the captain of the Super Eagles. There was a mix-up," Musa told reporters in Abuja.
“But right now, we have a new administration. Mikel is my senior and a big brother. So, Mikel is the captain, not me."
Mikel described Musa as a “wonderful professional", commending his courage to surrender the captaincy to him.
“I want to thank Ahmed Musa for being a wonderful professional," he said.
“It takes a man to come out and do what Ahmed Musa has done today. So, I commend him a lot for doing that."
Mikel will now lead Nigeria in Friday’s crucial 2017 Africa Cup of Nations qualifier against Egypt in the northern city of Kaduna.
Last year, CSKA Moscow forward Musa was named the country’s skipper by former Super Eagles coach Sunday Oliseh, instead of vice-captain Mikel following the retirement of Vincent Enyeama from international football.
Mikel, 28, made his full international debut in 2005, five years before the 23-year-old Musa.